Commit Graph

312 Commits

Author SHA1 Message Date
Stefan Pintilie f384606799 [PowerPC] Emit xscpsgndp instead of xxlor when copying floating point scalar registers for P9
This patch will address using the xscpsgndp instruction to copy floating point
scalar registers instead of the xxlor (specifically XXLORf) instruction that is
currently used. Additionally, this patch of utilizing xscpsgndp will apply to
P9, while pre-P9 will still use xxlor.

Patch by amyk

Differential Revision: https://reviews.llvm.org/D50004

llvm-svn: 340643
2018-08-24 20:00:24 +00:00
QingShan Zhang f8f9af7ba5 [PowerPC] Add a peephole post RA to transform the inst that fed by add
If the arch is P8, we will select XFLOAD to load the floating point, and then, expand it to vsx and non-vsx X-form instruction post RA. This patch is trying to convert the X-form to D-form if it meets the requirement that one operand of the x-form inst is the special Zero register, and another operand fed by add inst. i.e.
y = add imm, reg
LFDX. 0, y
-->
LFD imm(reg)

Reviewers: Nemanjai
Differential Revision: https://reviews.llvm.org/D49007

llvm-svn: 340149
2018-08-20 02:52:55 +00:00
Fangrui Song f78650a8de Remove trailing space
sed -Ei 's/[[:space:]]+$//' include/**/*.{def,h,td} lib/**/*.{cpp,h}

llvm-svn: 338293
2018-07-30 19:41:25 +00:00
Justin Hibbits d52990c71b Introduce codegen for the Signal Processing Engine
Summary:
The Signal Processing Engine (SPE) is found on NXP/Freescale e500v1,
e500v2, and several e200 cores.  This adds support targeting the e500v2,
as this is more common than the e500v1, and is in SoCs still on the
market.

This patch is very intrusive because the SPE is binary incompatible with
the traditional FPU.  After discussing with others, the cleanest
solution was to make both SPE and FPU features on top of a base PowerPC
subset, so all FPU instructions are now wrapped with HasFPU predicates.

Supported by this are:
* Code generation following the SPE ABI at the LLVM IR level (calling
conventions)
* Single- and Double-precision math at the level supported by the APU.

Still to do:
* Vector operations
* SPE intrinsics

As this changes the Callee-saved register list order, one test, which
tests the precise generated code, was updated to account for the new
register order.

Reviewed by: nemanjai
Differential Revision: https://reviews.llvm.org/D44830

llvm-svn: 337347
2018-07-18 04:25:10 +00:00
Nemanja Ivanovic 080c35050e [PowerPC] Materialize more constants with CR-field set in late peephole
Revision r322373 fixed a bug in how we materialize constants when the CR-field
needs to be set.

However the fix is overly conservative. It will only do the transform if
AND-ing the input with the new constant produces the same new constant.
This is of course correct, but not necessarily required.

If there are no futher uses of the constant, the constant can be changed.
If there are no uses of the GPR result, the final result of the materialization
isn't important other than it needs to compare to zero correctly (lt, gt, eq).

Differential revision: https://reviews.llvm.org/D42109

llvm-svn: 337008
2018-07-13 15:21:03 +00:00
QingShan Zhang 9f0fe9a3f8 If the arch is P9, we will select the DFLOADf32/DFLOADf64 pseudo instruction when we are loading a floating,
and expand it post RA basing on the register pressure. However, we miss to do the add-imm peephole for these pseudo instruction.

Differential Revision: https://reviews.llvm.org/D47568
Reviewed By: Nemanjai

llvm-svn: 335024
2018-06-19 06:54:51 +00:00
Hiroshi Inoue 0f7f59f073 [PowerPC] fix trivial typos in comment, NFC
llvm-svn: 334583
2018-06-13 08:54:13 +00:00
Nicola Zaghen d34e60ca85 Rename DEBUG macro to LLVM_DEBUG.
The DEBUG() macro is very generic so it might clash with other projects.
The renaming was done as follows:
- git grep -l 'DEBUG' | xargs sed -i 's/\bDEBUG\s\?(/LLVM_DEBUG(/g'
- git diff -U0 master | ../clang/tools/clang-format/clang-format-diff.py -i -p1 -style LLVM
- Manual change to APInt
- Manually chage DOCS as regex doesn't match it.

In the transition period the DEBUG() macro is still present and aliased
to the LLVM_DEBUG() one.

Differential Revision: https://reviews.llvm.org/D43624

llvm-svn: 332240
2018-05-14 12:53:11 +00:00
Nemanja Ivanovic c564dc060a [PowerPC] Fix condition for 64-bit rotate when replacing r+r instr with r+i
This patch fixes https://bugs.llvm.org/show_bug.cgi?id=37039
The condition only covers one of the two 64-bit rotate instructions. This just
adds the second (RLDICLo).

Patch by Josh Stone.

llvm-svn: 329852
2018-04-11 21:25:44 +00:00
Stefan Pintilie 26d4f923c4 [PowerPC] Infrastructure work. Implement getting the opcode for a spill in one place.
A new function getOpcodeForSpill should now be the only place to get
the opcode for a given spilled register.

Differential Revision: https://reviews.llvm.org/D43086

llvm-svn: 328556
2018-03-26 17:39:18 +00:00
Zaara Syeda 6535993625 Re-commit: [MachineLICM] Add functions to MachineLICM to hoist invariant stores
This patch adds functions to allow MachineLICM to hoist invariant stores.
Currently, MachineLICM does not hoist any store instructions, however
when storing the same value to a constant spot on the stack, the store
instruction should be considered invariant and be hoisted. The function
isInvariantStore iterates each operand of the store instruction and checks
that each register operand satisfies isCallerPreservedPhysReg. The store
may be fed by a copy, which is hoisted by isCopyFeedingInvariantStore.
This patch also adds the PowerPC changes needed to consider the stack
register as caller preserved.

Differential Revision: https://reviews.llvm.org/D40196

llvm-svn: 328326
2018-03-23 15:28:15 +00:00
Zaara Syeda 01f414baaa Revert [MachineLICM] This reverts commit rL327856
Failing build bots. Revert the commit now.

llvm-svn: 327864
2018-03-19 16:19:44 +00:00
Zaara Syeda ff05e2b0e6 [MachineLICM] Add functions to MachineLICM to hoist invariant stores
This patch adds functions to allow MachineLICM to hoist invariant stores.
Currently, MachineLICM does not hoist any store instructions, however
when storing the same value to a constant spot on the stack, the store
instruction should be considered invariant and be hoisted. The function
isInvariantStore iterates each operand of the store instruction and checks
that each register operand satisfies isCallerPreservedPhysReg. The store
may be fed by a copy, which is hoisted by isCopyFeedingInvariantStore.
This patch also adds the PowerPC changes needed to consider the stack
register as caller preserved.

Differential Revision: https://reviews.llvm.org/D40196

llvm-svn: 327856
2018-03-19 14:52:25 +00:00
Nemanja Ivanovic 6cc31ca814 [PowerPC] Do not emit record-form rotates when record-form andi suffices
Up until Power9, the performance profile for rlwinm., rldicl. and andi. looked
more or less equivalent. However with Power9, the rotates are still 2-way
cracked whereas the and-immediate is not.

This patch just ensures that we don't emit record-form rotates when an andi.
is adequate.

As first pointed out by Carrot in https://bugs.llvm.org/show_bug.cgi?id=30833
(this patch is a fix for that PR).

Differential Revision: https://reviews.llvm.org/D43977

llvm-svn: 326736
2018-03-05 19:27:16 +00:00
Benjamin Kramer 309124e0b1 [PowerPC] Don't miscompile rotate+mask into an ANDIo if it can't recreate the immediate
I'm not even sure if this transform is ever worth it, but this at least
stops the bleeding.

llvm-svn: 322373
2018-01-12 15:03:24 +00:00
Nemanja Ivanovic 4e1f5e0734 [PowerPC] Fix for PR35688 - handle out-of-range values for r+r to r+i conversion
Revision 320791 introduced a pass that transforms reg+reg instructions to
reg+imm if they're fed by "load immediate". However, it didn't
handle out-of-range shifts correctly as reported in PR35688.
This patch fixes that and therefore the PR.

Furthermore, there was undefined behaviour in the patch where the RHS of an
initialization expression was 32 bits and constant `1` was shifted left 32
bits. This was fixed by ensuring the RHS is 64 bits just like the LHS.

Differential Revision: https://reviews.llvm.org/D41369

llvm-svn: 321551
2017-12-29 12:22:27 +00:00
Matthias Braun f1caa2833f MachineFunction: Return reference from getFunction(); NFC
The Function can never be nullptr so we can return a reference.

llvm-svn: 320884
2017-12-15 22:22:58 +00:00
Nemanja Ivanovic 6ab32dea12 Fix the second build bot break introduced by r320791.
llvm-svn: 320811
2017-12-15 14:17:45 +00:00
Nemanja Ivanovic 1794cdc481 Fix code causing fallthrough warnings in the PPC back end.
llvm-svn: 320806
2017-12-15 11:47:48 +00:00
Nemanja Ivanovic 74ecf59cc0 Fix the build bot break introduced by r320791.
llvm-svn: 320798
2017-12-15 09:51:34 +00:00
Nemanja Ivanovic 6995e5dae7 [PowerPC] Convert r+r instructions to r+i (pre and post RA)
This patch adds the necessary infrastructure to convert instructions that
take two register operands to those that take a register and immediate if
the necessary operand is produced by a load-immediate. Furthermore, it uses
this infrastructure to perform such conversions twice - first at MachineSSA
and then pre-emit.

There are a number of reasons we may end up with opportunities for this
transformation, including but not limited to:
- X-Form instructions chosen since the exact offset isn't available at ISEL time
- Atomic instructions with constant operands (we will add patterns for this
  in the future)
- Tail duplication may duplicate code where one block contains this redundancy
- When emitting compare-free code in PPCDAGToDAGISel, we don't handle constant
  comparands specially

Furthermore, this patch moves the initialization of PPCMIPeepholePass so that
it can be used for MIR tests.

llvm-svn: 320791
2017-12-15 07:27:53 +00:00
Francis Visoiu Mistrih 5df3bbf3e6 [CodeGen] Print global addresses as @foo in both MIR and debug output
Work towards the unification of MIR and debug output by printing
`@foo` instead of `<ga:@foo>`.

Also print target flags in the MIR format since most of them are used on
global address operands.

Only debug syntax is affected.

llvm-svn: 320682
2017-12-14 10:03:09 +00:00
Matthias Braun f842297d50 Rename LiveIntervalAnalysis.h to LiveIntervals.h
Headers/Implementation files should be named after the class they
declare/define.

Also eliminated an `#include "llvm/CodeGen/LiveIntervalAnalysis.h"` in
favor of `class LiveIntarvals;`

llvm-svn: 320546
2017-12-13 02:51:04 +00:00
Francis Visoiu Mistrih a8a83d150f [CodeGen] Use MachineOperand::print in the MIRPrinter for MO_Register.
Work towards the unification of MIR and debug output by refactoring the
interfaces.

For MachineOperand::print, keep a simple version that can be easily called
from `dump()`, and a more complex one which will be called from both the
MIRPrinter and MachineInstr::print.

Add extra checks inside MachineOperand for detached operands (operands
with getParent() == nullptr).

https://reviews.llvm.org/D40836

* find . \( -name "*.mir" -o -name "*.cpp" -o -name "*.h" -o -name "*.ll" -o -name "*.s" \) -type f -print0 | xargs -0 sed -i '' -E 's/kill: ([^ ]+) ([^ ]+)<def> ([^ ]+)/kill: \1 def \2 \3/g'
* find . \( -name "*.mir" -o -name "*.cpp" -o -name "*.h" -o -name "*.ll" -o -name "*.s" \) -type f -print0 | xargs -0 sed -i '' -E 's/kill: ([^ ]+) ([^ ]+) ([^ ]+)<def>/kill: \1 \2 def \3/g'
* find . \( -name "*.mir" -o -name "*.cpp" -o -name "*.h" -o -name "*.ll" -o -name "*.s" \) -type f -print0 | xargs -0 sed -i '' -E 's/kill: def ([^ ]+) ([^ ]+) ([^ ]+)<def>/kill: def \1 \2 def \3/g'
* find . \( -name "*.mir" -o -name "*.cpp" -o -name "*.h" -o -name "*.ll" -o -name "*.s" \) -type f -print0 | xargs -0 sed -i '' -E 's/<def>//g'
* find . \( -name "*.mir" -o -name "*.cpp" -o -name "*.h" -o -name "*.ll" -o -name "*.s" \) -type f -print0 | xargs -0 sed -i '' -E 's/([^ ]+)<kill>/killed \1/g'
* find . \( -name "*.mir" -o -name "*.cpp" -o -name "*.h" -o -name "*.ll" -o -name "*.s" \) -type f -print0 | xargs -0 sed -i '' -E 's/([^ ]+)<imp-use,kill>/implicit killed \1/g'
* find . \( -name "*.mir" -o -name "*.cpp" -o -name "*.h" -o -name "*.ll" -o -name "*.s" \) -type f -print0 | xargs -0 sed -i '' -E 's/([^ ]+)<dead>/dead \1/g'
* find . \( -name "*.mir" -o -name "*.cpp" -o -name "*.h" -o -name "*.ll" -o -name "*.s" \) -type f -print0 | xargs -0 sed -i '' -E 's/([^ ]+)<def[ ]*,[ ]*dead>/dead \1/g'
* find . \( -name "*.mir" -o -name "*.cpp" -o -name "*.h" -o -name "*.ll" -o -name "*.s" \) -type f -print0 | xargs -0 sed -i '' -E 's/([^ ]+)<imp-def[ ]*,[ ]*dead>/implicit-def dead \1/g'
* find . \( -name "*.mir" -o -name "*.cpp" -o -name "*.h" -o -name "*.ll" -o -name "*.s" \) -type f -print0 | xargs -0 sed -i '' -E 's/([^ ]+)<imp-def>/implicit-def \1/g'
* find . \( -name "*.mir" -o -name "*.cpp" -o -name "*.h" -o -name "*.ll" -o -name "*.s" \) -type f -print0 | xargs -0 sed -i '' -E 's/([^ ]+)<imp-use>/implicit \1/g'
* find . \( -name "*.mir" -o -name "*.cpp" -o -name "*.h" -o -name "*.ll" -o -name "*.s" \) -type f -print0 | xargs -0 sed -i '' -E 's/([^ ]+)<internal>/internal \1/g'
* find . \( -name "*.mir" -o -name "*.cpp" -o -name "*.h" -o -name "*.ll" -o -name "*.s" \) -type f -print0 | xargs -0 sed -i '' -E 's/([^ ]+)<undef>/undef \1/g'

llvm-svn: 320022
2017-12-07 10:40:31 +00:00
Francis Visoiu Mistrih 93ef145862 [CodeGen] Print "%vreg0" as "%0" in both MIR and debug output
As part of the unification of the debug format and the MIR format, avoid
printing "vreg" for virtual registers (which is one of the current MIR
possibilities).

Basically:

* find . \( -name "*.mir" -o -name "*.cpp" -o -name "*.h" -o -name "*.ll" \) -type f -print0 | xargs -0 sed -i '' -E "s/%vreg([0-9]+)/%\1/g"
* grep -nr '%vreg' . and fix if needed
* find . \( -name "*.mir" -o -name "*.cpp" -o -name "*.h" -o -name "*.ll" \) -type f -print0 | xargs -0 sed -i '' -E "s/ vreg([0-9]+)/ %\1/g"
* grep -nr 'vreg[0-9]\+' . and fix if needed

Differential Revision: https://reviews.llvm.org/D40420

llvm-svn: 319427
2017-11-30 12:12:19 +00:00
Sean Fertile aab3ef76d9 [PowerPC] Relax the checking on AND/AND8 in isSignOrZeroExtended.
Separate the handling of AND/AND8 out from PHI/OR/ISEL checking. The reasoning
is the others need all their operands to be sign/zero extended for their output
to also be sign/zero extended. This is true for AND and sign-extension, but for
zero-extension we only need at least one of the input operands to be zero
extended for the result to also be zero extended.

Differential Revision: https://reviews.llvm.org/D39078

llvm-svn: 319289
2017-11-29 04:09:29 +00:00
Francis Visoiu Mistrih 9d7bb0cb40 [CodeGen] Print register names in lowercase in both MIR and debug output
As part of the unification of the debug format and the MIR format,
always print registers as lowercase.

* Only debug printing is affected. It now follows MIR.

Differential Revision: https://reviews.llvm.org/D40417

llvm-svn: 319187
2017-11-28 17:15:09 +00:00
Zaara Syeda f94d58d908 [PowerPC] Remove redundant TOC saves
This patch adds a peep hole optimization to remove any redundant toc save
instructions added as part of the call sequence for indirect calls. It removes
any toc saves within a function that are dominated by another toc save.

Differential Revision: https://reviews.llvm.org/D39736

llvm-svn: 319087
2017-11-27 20:26:36 +00:00
Tony Jiang 438bf4a66b [PPC] Heuristic to choose between a X-Form VSX ld/st vs a X-Form FP ld/st.
The VSX versions have the advantage of a full 64-register target whereas the FP
ones have the advantage of lower latency and higher throughput. So what we’re
after is using the faster instructions in low register pressure situations and
using the larger register file in high register pressure situations.

The heuristic chooses between the following 7 pairs of instructions.
PPC::LXSSPX vs PPC::LFSX
PPC::LXSDX vs PPC::LFDX
PPC::STXSSPX vs PPC::STFSX
PPC::STXSDX vs PPC::STFDX
PPC::LXSIWAX vs PPC::LFIWAX
PPC::LXSIWZX vs PPC::LFIWZX
PPC::STXSIWX vs PPC::STFIWX

Differential Revision: https://reviews.llvm.org/D38486

llvm-svn: 318651
2017-11-20 14:38:30 +00:00
Hiroshi Inoue b72b1fb0de [PowerPC] Use record-form instruction for Less-or-Equal -1 and Greater-or-Equal 1
Currently a record-form instruction is used for comparison of "greater than -1" and "less than 1" by modifying the predicate (e.g. LT 1 into LE 0) in addition to the naive case of comparison against 0.
This patch also enables emitting a record-form instruction for "less than or equal to -1" (i.e. "less than 0") and "greater than or equal to 1" (i.e. "greater than 0") to increase the optimization opportunities.

Differential Revision: https://reviews.llvm.org/D38941

llvm-svn: 316647
2017-10-26 09:01:51 +00:00
Hiroshi Inoue 5388e66d3a [PowerPC] Use helper functions to check sign-/zero-extended value
Helper functions to identify sign- and zero-extending machine instruction is introduced in rL315888.
This patch makes PPCInstrInfo::optimizeCompareInstr use the helper functions. It simplifies the code and also makes possible more optimizations since the helper can do more analysis than the original check code; I observed about 5000 more compare instructions are eliminated while building LLVM.

Also, this patch fixes a bug in helpers on ANDIo instruction handling due to the order of checks. This bug causes a failure in an existing test case for optimizeCompareInstr.

Differential Revision: https://reviews.llvm.org/D38988

llvm-svn: 316071
2017-10-18 10:31:19 +00:00
Hiroshi Inoue a7eb78b47f [PowerPC] fix up in sign-/zero-extension elimination
This patch fixes a potential problem in my previous commit (https://reviews.llvm.org/rL315888) by adding a null check.

llvm-svn: 315900
2017-10-16 12:11:15 +00:00
Hiroshi Inoue e3a3e3c9e9 [PowerPC] Eliminate sign- and zero-extensions if already sign- or zero-extended
This patch enables redundant sign- and zero-extension elimination in PowerPC MI Peephole pass.
If the input value of a sign- or zero-extension is known to be already sign- or zero-extended, the operation is redundant and can be eliminated.
One common case is sign-extensions for a method parameter or for a method return value; they must be sign- or zero-extended as defined in PPC ELF ABI. 
For example of the following simple code, two extsw instructions are generated before the invocation of int_func and before the return. With this patch, both extsw are eliminated.

void int_func(int);
void ii_test(int a) {
    if (a & 1) return int_func(a);
}

Such redundant sign- or zero-extensions are quite common in many programs; e.g. I observed about 60,000 occurrences of the elimination while compiling the LLVM+CLANG.

Differential Revision: https://reviews.llvm.org/D31319

llvm-svn: 315888
2017-10-16 04:12:57 +00:00
Lei Huang 263dc4ef3a [PowerPC] Utilize DQ-Form instructions for spill/restore and fix FrameIndex elimination to only use `lis/addi` if necessary.
Currently we produce a bunch of unnecessary code when emitting the
prologue/epilogue for spills/restores.  Namely, if the load from stack
slot/store to stack slot instruction is an X-Form instruction, we will
always produce an LIS/ORI sequence for the stack offset.

Furthermore, we have not exploited the P9 vector D-Form loads/stores for this
purpose.

This patch address both issues.

Specifying the D-Form load as the instruction to use for stack spills/reloads
should be safe because:

1. The stack should be aligned according to the ABI
2. If the stack isn't aligned, PPCRegisterInfo::eliminateFrameIndex() will
   check for the offset being a multiple of 16 and will convert it to an
   X-Form instruction if it isn't.

Differential Revision : https://reviews.llvm.org/D38758

llvm-svn: 315500
2017-10-11 20:20:58 +00:00
Hiroshi Inoue ed1ffa49a4 [PowerPC] eliminate unconditional branch to the next instruction
This patch makes analyzeBranch eliminate unconditional branch to the next instruction.
After basic blocks are re-organized by optimizers, such as machine block placement, a BB may end with an unconditional branch to the next (fallthrough) BB. This patch removes such redundant branch instruction.

Differential Revision: https://reviews.llvm.org/D37730

llvm-svn: 314297
2017-09-27 10:33:02 +00:00
Zaara Syeda fcd9697d72 [Power9] Spill gprs to vector registers rather than stack
This patch updates register allocation to enable spilling gprs to
volatile vector registers rather than the stack. It can be enabled
 for Power9 with option -ppc-enable-gpr-to-vsr-spills.

Differential Revision: https://reviews.llvm.org/D34815

llvm-svn: 313886
2017-09-21 16:12:33 +00:00
Hiroshi Inoue 967dc58ac1 [PowerPC] enable optimizeCompareInstr for branch with static branch hint
In optimizeCompareInstr, a compare instruction is eliminated by using a record form instruction if possible.
If the branch instruction that uses the result of the compare has a static branch hint, the optimization does not happen.
This patch makes this optimization happen regardless of the branch hint by splitting branch hint and branch condition before checking the predicate to identify the possible optimizations.

Differential Revision: https://reviews.llvm.org/D35801

llvm-svn: 309255
2017-07-27 08:14:48 +00:00
Hiroshi Inoue 393ef84cb6 fix formatting issue; NFC
llvm-svn: 308305
2017-07-18 13:31:40 +00:00
Lei Huang 84dbbfdeb9 [PowerPC] define target hook isReallyTriviallyReMaterializable()
Define target hook isReallyTriviallyReMaterializable() to explicitly specify
PowerPC instructions that are trivially rematerializable.  This will allow
the MachineLICM pass to accurately identify PPC instructions that should always
be hoisted.

Differential Revision: https://reviews.llvm.org/D34255

llvm-svn: 305932
2017-06-21 17:17:56 +00:00
Hiroshi Inoue 7a08bb1458 [PowerPC] fix potential verification errors on CFENCE8
This patch fixes a potential verification error (64-bit register operands for cmpw) with -verify-machineinstrs.

Differential Revision: https://reviews.llvm.org/D34208

llvm-svn: 305479
2017-06-15 16:51:28 +00:00
Nemanja Ivanovic e597bd8230 [PowerPC] Eliminate integer compare instructions - vol. 2
This patch builds upon https://reviews.llvm.org/rL302810 to add
handling for bitwise logical operations in general purpose registers.
The idea is to keep the values in GPRs as long as possible - only
extracting them to a condition register bit when no further operations
are to be done.

Differential Revision: https://reviews.llvm.org/D31851

llvm-svn: 304282
2017-05-31 05:40:25 +00:00
Hiroshi Inoue e3c14ebbfa [PPC] Fix assertion failure during binary encoding with -mcpu=pwr9
Summary
clang -c -mcpu=pwr9 test/CodeGen/PowerPC/build-vector-tests.ll causes an assertion failure during the binary encoding.
The failure occurs when a D-form load instruction takes two register operands instead of a register + an immediate.

This patch fixes the problem and also adds an assertion to catch this failure earlier before the binary encoding (i.e. during lit test).
The fix is from Nemanja Ivanovic @nemanjai.

Differential Revision: https://reviews.llvm.org/D33482

llvm-svn: 304133
2017-05-29 07:12:39 +00:00
Hiroshi Inoue 37e63b1b21 Summary
PPC backend eliminates compare instructions by using record-form instructions in PPCInstrInfo::optimizeCompareInstr, which is called from peephole optimization pass.
This patch improves this optimization to eliminate more compare instructions in two types of common case.


- comparison against a constant 1 or -1

The record-form instructions set CR bit based on signed comparison against 0. So, the current implementation does not exploit the record-form instruction for comparison against a non-zero constant.
This patch enables record-form optimization for constant of 1 or -1 if possible; it changes the condition "greater than -1" into "greater than or equal to 0" and "less than 1" into "less than or equal to 0".
With this patch, compare can be eliminated in the following code sequence, as an example.

uint64_t a, b;
if ((a | b) & 0x8000000000000000ull) { ... }
else { ... }


- andi for 32-bit comparison on PPC64

Since record-form instructions execute 64-bit signed comparison and so we have limitation in eliminating 32-bit comparison, i.e. with cmplwi, using the record-form. The original implementation already has such checks but andi. is not recognized as an instruction which executes implicit zero extension and hence safe to convert into record-form if used for equality check.

%1 = and i32 %a, 10
%2 = icmp ne i32 %1, 0
br i1 %2, label %foo, label %bar

In this simple example, LLVM generates andi. + cmplwi + beq on PPC64.
This patch make it possible to eliminate the cmplwi for this case.
I added andi. for optimization targets if it is safe to do so.

Differential Revision: https://reviews.llvm.org/D30081

llvm-svn: 303500
2017-05-21 06:00:05 +00:00
Tim Shen 3bef27cc6f [PPC] Lower load acquire/seq_cst trailing fence to cmp + bne + isync.
Summary:
This fixes pr32392.

The lowering pipeline is:
llvm.ppc.cfence in IR -> PPC::CFENCE8 in isel -> Actual instructions in
expandPostRAPseudo.

The reason why expandPostRAPseudo is chosen is because previous passes
are likely eliminating instructions like cmpw 3, 3 (early CSE) and bne-
7, .+4 (some branch pass(s)).

Differential Revision: https://reviews.llvm.org/D32763

llvm-svn: 303205
2017-05-16 20:18:06 +00:00
Hans Wennborg 9b9a5358dd Re-commit r301040 "X86: Don't emit zero-byte functions on Windows"
In addition to the original commit, tighten the condition for when to
pad empty functions to COFF Windows.  This avoids running into problems
when targeting e.g. Win32 AMDGPU, which caused test failures when this
was committed initially.

llvm-svn: 301047
2017-04-21 21:48:41 +00:00
Hans Wennborg 04593000d8 Revert r301040 "X86: Don't emit zero-byte functions on Windows"
This broke almost all bots. Reverting while fixing.

llvm-svn: 301041
2017-04-21 21:10:37 +00:00
Hans Wennborg cb3e810714 X86: Don't emit zero-byte functions on Windows
Empty functions can lead to duplicate entries in the Guard CF Function
Table of a binary due to multiple functions sharing the same RVA,
causing the kernel to refuse to load that binary.

We had a terrific bug due to this in Chromium.

It turns out we were already doing this for Mach-O in certain
situations. This patch expands the code for that in
AsmPrinter::EmitFunctionBody() and renames
TargetInstrInfo::getNoopForMachoTarget() to simply getNoop() since it
seems it was used for not just Mach-O anyway.

Differential Revision: https://reviews.llvm.org/D32330

llvm-svn: 301040
2017-04-21 20:58:12 +00:00
Eric Christopher f48ef3355f Remove an oddly unnecessary temporary.
llvm-svn: 298888
2017-03-27 22:40:51 +00:00
Krzysztof Parzyszek cc31871dc4 Make TargetInstrInfo::isPredicable take a const reference, NFC
llvm-svn: 296901
2017-03-03 18:30:54 +00:00
Tim Shen 918ed871df [XRay] Implement powerpc64le xray.
Summary:
powerpc64 big-endian is not supported, but I believe that most logic can
be shared, except for xray_powerpc64.cc.

Also add a function InvalidateInstructionCache to xray_util.h, which is
copied from llvm/Support/Memory.cpp. I'm not sure if I need to add a unittest,
and I don't know how.

Reviewers: dberris, echristo, iteratee, kbarton, hfinkel

Subscribers: mehdi_amini, nemanjai, mgorny, llvm-commits

Differential Revision: https://reviews.llvm.org/D29742

llvm-svn: 294781
2017-02-10 21:03:24 +00:00