Before, only Thumb functions were marked as ".code 16". These
".code x" directives are effective until the next directive of its
kind is encountered. Therefore, in code with interleaved ARM and
Thumb functions, it was possible to declare a function as ARM and
end up with a Thumb function after assembly. A test has been added.
An existing test has also been fixed to take this change into
account.
Reviewers: aschwaighofer, t.p.northover, jmolloy, rengolin
Subscribers: aemerson, rengolin, llvm-commits
Differential Revision: https://reviews.llvm.org/D24337
llvm-svn: 281324
For the common pattern (CMPZ (AND x, #bitmask), #0), we can do some more efficient instruction selection if the bitmask is one consecutive sequence of set bits (32 - clz(bm) - ctz(bm) == popcount(bm)).
1) If the bitmask touches the LSB, then we can remove all the upper bits and set the flags by doing one LSLS.
2) If the bitmask touches the MSB, then we can remove all the lower bits and set the flags with one LSRS.
3) If the bitmask has popcount == 1 (only one set bit), we can shift that bit into the sign bit with one LSLS and change the condition query from NE/EQ to MI/PL (we could also implement this by shifting into the carry bit and branching on BCC/BCS).
4) Otherwise, we can emit a sequence of LSLS+LSRS to remove the upper and lower zero bits of the mask.
1-3 require only one 16-bit instruction and can elide the CMP. 4 requires two 16-bit instructions but can elide the CMP and doesn't require materializing a complex immediate, so is also a win.
llvm-svn: 281323
If a constant is unamed_addr and is only used within one function, we can save
on the code size and runtime cost of an indirection by changing the global's storage
to inside the constant pool. For example, instead of:
ldr r0, .CPI0
bl printf
bx lr
.CPI0: &format_string
format_string: .asciz "hello, world!\n"
We can emit:
adr r0, .CPI0
bl printf
bx lr
.CPI0: .asciz "hello, world!\n"
This can cause significant code size savings when many small strings are used in one
function (4 bytes per string).
llvm-svn: 281314
This patch reverses the edge from DIGlobalVariable to GlobalVariable.
This will allow us to more easily preserve debug info metadata when
manipulating global variables.
Fixes PR30362. A program for upgrading test cases is attached to that
bug.
Differential Revision: http://reviews.llvm.org/D20147
llvm-svn: 281284
For the common pattern (CMPZ (AND x, #bitmask), #0), we can do some more efficient instruction selection if the bitmask is one consecutive sequence of set bits (32 - clz(bm) - ctz(bm) == popcount(bm)).
1) If the bitmask touches the LSB, then we can remove all the upper bits and set the flags by doing one LSLS.
2) If the bitmask touches the MSB, then we can remove all the lower bits and set the flags with one LSRS.
3) If the bitmask has popcount == 1 (only one set bit), we can shift that bit into the sign bit with one LSLS and change the condition query from NE/EQ to MI/PL (we could also implement this by shifting into the carry bit and branching on BCC/BCS).
4) Otherwise, we can emit a sequence of LSLS+LSRS to remove the upper and lower zero bits of the mask.
1-3 require only one 16-bit instruction and can elide the CMP. 4 requires two 16-bit instructions but can elide the CMP and doesn't require materializing a complex immediate, so is also a win.
llvm-svn: 281215
If a constant is unamed_addr and is only used within one function, we can save
on the code size and runtime cost of an indirection by changing the global's storage
to inside the constant pool. For example, instead of:
ldr r0, .CPI0
bl printf
bx lr
.CPI0: &format_string
format_string: .asciz "hello, world!\n"
We can emit:
adr r0, .CPI0
bl printf
bx lr
.CPI0: .asciz "hello, world!\n"
This can cause significant code size savings when many small strings are used in one
function (4 bytes per string).
llvm-svn: 281213
Summary:
This test was not testing the intrinsics. A function like this:
define %v4f32 @test_v4f32.floor(%v4f32 %a){
...
%1 = call %v4f32 @llvm.floor.v4f32(%v4f32 %a)
...
}
is transformed into the following assembly:
_test_v4f32.floor: @ @test_v4f32.floor
...
bl _floorf
...
In each function tested, there are two CHECK: one that checked
for the label and another one for the intrinsic that should be used
inside the function (in our case, "floor"). However, although the
first CHECK was matching the label, the second was not matching the
intrinsic, but the second "floor" in the same line as the label.
This is fixed by making the first CHECK match the entire line.
Reviewers: jmolloy, rengolin
Subscribers: rengolin, llvm-commits
Differential Revision: https://reviews.llvm.org/D24398
llvm-svn: 281211
The CMPZ #0 disappears during peepholing, leaving just a tADDi3, tADDi8 or t2ADDri. This avoids having to materialize the expensive negative constant in Thumb-1, and allows a shrinking from a 32-bit CMN to a 16-bit ADDS in Thumb-2.
llvm-svn: 281040
And associated commits, as they broke the Thumb bots.
This reverts commit r280935.
This reverts commit r280891.
This reverts commit r280888.
llvm-svn: 280967
Materializing something like "-3" can be done as 2 instructions:
MOV r0, #3
MVN r0, r0
This has a cost of 2, not 3. It looks like we were already trying to detect this pattern in TII::getIntImmCost(), but were taking the complement of the zero-extended value instead of the sign-extended value which is unlikely to ever produce a number < 256.
There were no tests failing after changing this... :/
llvm-svn: 280928
This reverts commit r280808.
It is possible that this change results in an infinite loop. This
is causing timeouts in some tests on ARM, and a Chromebook bot is
failing.
llvm-svn: 280918
This is a port of XRay to ARM 32-bit, without Thumb support yet. The XRay instrumentation support is moving up to AsmPrinter.
This is one of 3 commits to different repositories of XRay ARM port. The other 2 are:
1. https://reviews.llvm.org/D23932 (Clang test)
2. https://reviews.llvm.org/D23933 (compiler-rt)
Differential Revision: https://reviews.llvm.org/D23931
llvm-svn: 280888
Summary:
This saves a library call to __aeabi_uidivmod. However, the
processor must feature hardware division in order to benefit from
the transformation.
Reviewers: scott-0, jmolloy, compnerd, rengolin
Subscribers: t.p.northover, compnerd, aemerson, rengolin, samparker, llvm-commits
Differential Revision: https://reviews.llvm.org/D24133
llvm-svn: 280808
This is a Windows ARM specific issue. If the code path in the if conversion
ends up using a relocation which will form a IMAGE_REL_ARM_MOV32T, we end up
with a bundle to ensure that the mov.w/mov.t pair is not split up. This is
normally fine, however, if the branch is also predicated, then we end up trying
to predicate the bundle.
For now, report a bundle as being unpredicatable. Although this is false, this
would trigger a failure case previously anyways, so this is no worse. That is,
there should not be any code which would previously have been if converted and
predicated which would not be now.
Under certain circumstances, it may be possible to "predicate the bundle". This
would require scanning all bundle instructions, and ensure that the bundle
contains only predicatable instructions, and converting the bundle into an IT
block sequence. If the bundle is larger than the maximal IT block length (4
instructions), it would require materializing multiple IT blocks from the single
bundle.
llvm-svn: 280689
All of the builtins are designed to be invoked with ARM AAPCS CC even on ARM
AAPCS VFP CC hosts. Tweak the default initialisation to ARM AAPCS CC rather
than C CC for ARM/thumb targets.
The changes to the tests are necessary to ensure that the calling convention for
the lowered library calls are honoured. Furthermore, these adjustments cause
certain branch invocations to change to branch-and-link since the returned value
needs to be moved across registers (d0 -> r0, r1).
llvm-svn: 280683
types. This is the LLVM counterpart and it adds options that map onto FP
exceptions and denormal build attributes allowing better fp math library
selections.
Differential Revision: https://reviews.llvm.org/D24070
llvm-svn: 280246
Summary:
In fuctions that contained debug info but were empty otherwise,
the ARM load/store optimizer could abort. This was because
function MergeReturnIntoLDM handled the special case where a
Machine Basic BLock is empty by calling MBB.empty(). However, this
returns false in presence of debug info, although the function
should be considered empty in the eyes of the load/store optimizer.
This has been fixed by handling the case where searching through the
block finds only debug instructions.
Reviewers: rengolin, dexonsmith, llvm-commits, jmolloy
Subscribers: t.p.northover, aemerson, rengolin, samparker
Differential Revision: https://reviews.llvm.org/D23847
llvm-svn: 279820
Rename AllVRegsAllocated to NoVRegs. This avoids the connotation of
running after register and simply describes that no vregs are used in
a machine function. With that we can simply compute the property and do
not need to dump/parse it in .mir files.
Differential Revision: http://reviews.llvm.org/D23850
llvm-svn: 279698
tracksSubRegLiveness only depends on the Subtarget and a cl::opt, there
is not need to change it or save/parse it in a .mir file.
Make the field const and move the initialization LiveIntervalAnalysis to the
MachineRegisterInfo constructor. Also cleanup some code and fix some
instances which better use MachineRegisterInfo::subRegLivenessEnabled() instead
of TargetSubtargetInfo::enableSubRegLiveness().
llvm-svn: 279676
The cost of predicating a diamond is only the instructions that are not shared
between the two branches. Additionally If a predicate clobbering instruction
occurs in the shared portion of the branches (e.g. a cond move), it may still
be possible to if convert the sub-cfg. This change handles these two facts by
rescanning the non-shared portion of a diamond sub-cfg to recalculate both the
predication cost and whether both blocks are pred-clobbering.
Fixed 2 bugs before recommitting. Branch instructions must be compared and found
identical before diamond conversion. Also, predicate-clobbering instructions in
the shared prefix disqualifies a potential diamond conversion. Includes tests
for both.
llvm-svn: 279670
Specifying isSSA is an extra line at best and results in invalid MI at
worst. Compute the value instead.
Differential Revision: http://reviews.llvm.org/D22722
llvm-svn: 279600
There is not an official documented ABI for frame pointers in Thumb2,
but we should try to emit something which is useful.
We use r7 as the frame pointer for Thumb code, which currently means
that if a function needs to save a high register (r8-r11), it will get
pushed to the stack between the frame pointer (r7) and link register
(r14). This means that while a stack unwinder can follow the chain of
frame pointers up the stack, it cannot know the offset to lr, so does
not know which functions correspond to the stack frames.
To fix this, we need to push the callee-saved registers in two batches,
with the first push saving the low registers, fp and lr, and the second
push saving the high registers. This is already implemented, but
previously only used for iOS. This patch turns it on for all Thumb2
targets when frame pointers are required by the ABI, and the frame
pointer is r7 (Windows uses r11, so this isn't a problem there). If
frame pointer elimination is enabled we still emit a single push/pop
even if we need a frame pointer for other reasons, to avoid increasing
code size.
We must also ensure that lr is pushed to the stack when using a frame
pointer, so that we end up with a complete frame record. Situations that
could cause this were rare, because we already push lr in most
situations so that we can return using the pop instruction.
Differential Revision: https://reviews.llvm.org/D23516
llvm-svn: 279506
[Recommitting now an unrelated assertion in SROA is sorted out]
The new version has several advantages:
1) IMSHO it's more readable and neater
2) It handles loads and stores properly
3) It can handle any number of incoming blocks rather than just two. I'll be taking advantage of this in a followup patch.
With this change we can now finally sink load-modify-store idioms such as:
if (a)
return *b += 3;
else
return *b += 4;
=>
%z = load i32, i32* %y
%.sink = select i1 %a, i32 5, i32 7
%b = add i32 %z, %.sink
store i32 %b, i32* %y
ret i32 %b
When this works for switches it'll be even more powerful.
Round 4. This time we should handle all instructions correctly, and not replace any operands that need to be constant with variables.
This was really hard to determine safely, so the helper function should be put into the Instruction API. I'll do that as a followup.
llvm-svn: 279460
The new version has several advantages:
1) IMSHO it's more readable and neater
2) It handles loads and stores properly
3) It can handle any number of incoming blocks rather than just two. I'll be taking advantage of this in a followup patch.
With this change we can now finally sink load-modify-store idioms such as:
if (a)
return *b += 3;
else
return *b += 4;
=>
%z = load i32, i32* %y
%.sink = select i1 %a, i32 5, i32 7
%b = add i32 %z, %.sink
store i32 %b, i32* %y
ret i32 %b
When this works for switches it'll be even more powerful.
Round 4. This time we should handle all instructions correctly, and not replace any operands that need to be constant with variables.
This was really hard to determine safely, so the helper function should be put into the Instruction API. I'll do that as a followup.
llvm-svn: 279443
This fixes the crash from PR29072, where the MachineBasicBlock::iterator
wasn't being properly checked against MachineBasicBlock::end() before
iterating. This was another bug exposed by the new
ilist::iterator::operator*() assertion from r279314.
This testcase is poor quality. bugpoint couldn't reduce any further,
and I haven't had time to dig into what's going on so I can't invent a
better one. I didn't even get good CHECK lines in: this is just a
crasher.
I'm committing anyway since this is a real crash with an obvious fix,
but I'll leave PR29072 open and ask an ARM maintainer to help improve
the testcase.
llvm-svn: 279391
The new version has several advantages:
1) IMSHO it's more readable and neater
2) It handles loads and stores properly
3) It can handle any number of incoming blocks rather than just two. I'll be taking advantage of this in a followup patch.
With this change we can now finally sink load-modify-store idioms such as:
if (a)
return *b += 3;
else
return *b += 4;
=>
%z = load i32, i32* %y
%.sink = select i1 %a, i32 5, i32 7
%b = add i32 %z, %.sink
store i32 %b, i32* %y
ret i32 %b
When this works for switches it'll be even more powerful.
llvm-svn: 279229
This reverts commit r278660.
It causes downstream assertion failure in InstCombine on shuffle
instructions. Comes up in __mm_swizzle_epi32.
llvm-svn: 278672
The new version has several advantages:
1) IMSHO it's more readable and neater
2) It handles loads and stores properly
3) It can handle any number of incoming blocks rather than just two. I'll be taking advantage of this in a followup patch.
With this change we can now finally sink load-modify-store idioms such as:
if (a)
return *b += 3;
else
return *b += 4;
=>
%z = load i32, i32* %y
%.sink = select i1 %a, i32 5, i32 7
%b = add i32 %z, %.sink
store i32 %b, i32* %y
ret i32 %b
When this works for switches it'll be even more powerful.
llvm-svn: 278660
If a loop is not rotated (for example when optimizing for size), the latch is not the backedge. If we promote an expression to post-inc form, we not only increase register pressure and add a COPY for that IV expression but for all IVs!
Motivating testcase:
void f(float *a, float *b, float *c, int n) {
while (n-- > 0)
*c++ = *a++ + *b++;
}
It's imperative that the pointer increments be located in the latch block and not the header block; if not, we cannot use post-increment loads and stores and we have to keep both the post-inc and pre-inc values around until the end of the latch which bloats register usage.
llvm-svn: 278658
"insert_subreg, subreg_to_reg, and reg_sequence" instructions' after
adjusting some unittest checks.
This is to solve PR28852. The restriction was added at 2010 to make better register
coalescing. We assumed that it was not necessary any more. Testing results on x86
supported the assumption.
We will look closely to any performance impact it will bring and will be prepared
to help analyzing performance problem found on other architectures.
Differential Revision: https://reviews.llvm.org/D23210
llvm-svn: 278466
To fix PR28014, this patch restricts tail merging to blocks that belong to the
same loop after MBP.
Differential Revision: https://reviews.llvm.org/D23191
llvm-svn: 278463
This change makes it possible for tail-duplication and tail-merging to
be disjoint. By being less aggressive when merging during layout, there are no
overlapping cases between tail-duplication and tail-merging, provided the
thresholds are disjoint.
There is a remaining TODO to benchmark the succ_size() test for non-layout tail
merging.
llvm-svn: 278265
Created a Thumb2 predicated pattern matcher that uses Thumb2 and
HasT2ExtractPack and used it to redefine the patterns for sxta{b|h}
and uxta{b|h}. Also used the similar patterns to fill in isel pattern
gaps for the corresponding instructions in the ARM backend.
The patch is mainly changes to tests since most of this functionality
appears not to have been tested.
Differential Revision: https://reviews.llvm.org/D23273
llvm-svn: 278207
This patch adds support for some new relocation models to the ARM
backend:
* Read-only position independence (ROPI): Code and read-only data is accessed
PC-relative. The offsets between all code and RO data sections are known at
static link time. This does not affect read-write data.
* Read-write position independence (RWPI): Read-write data is accessed relative
to the static base register (r9). The offsets between all writeable data
sections are known at static link time. This does not affect read-only data.
These two modes are independent (they specify how different objects
should be addressed), so they can be used individually or together. They
are otherwise the same as the "static" relocation model, and are not
compatible with SysV-style PIC using a global offset table.
These modes are normally used by bare-metal systems or systems with
small real-time operating systems. They are designed to avoid the need
for a dynamic linker, the only initialisation required is setting r9 to
an appropriate value for RWPI code.
I have only added support to SelectionDAG, not FastISel, because
FastISel is currently disabled for bare-metal targets where these modes
would be used.
Differential Revision: https://reviews.llvm.org/D23195
llvm-svn: 278015
James Molloy