Currently the return address ABI registers s[30:31], which fall in the call
clobbered register range, are added as a live-in on the function entry to
preserve its value when we have calls so that it gets saved and restored
around the calls.
But the DWARF unwind information (CFI) needs to track where the return address
resides in a frame and the above approach makes it difficult to track the
return address when the CFI information is emitted during the frame lowering,
due to the involvment of understanding the control flow.
This patch moves the return address ABI registers s[30:31] into callee saved
registers range and stops adding live-in for return address registers, so that
the CFI machinery will know where the return address resides when CSR
save/restore happen during the frame lowering.
And doing the above poses an issue that now the return instruction uses undefined
register `sgpr30_sgpr31`. This is resolved by hiding the return address register
use by the return instruction through the `SI_RETURN` pseudo instruction, which
doesn't take any input operands, until the `SI_RETURN` pseudo gets lowered to the
`S_SETPC_B64_return` during the `expandPostRAPseudo()`.
As an added benefit, this patch simplifies overall return instruction handling.
Note: The AMDGPU CFI changes are there only in the downstream code and another
version of this patch will be posted for review for the downstream code.
Reviewed By: arsenm
Differential Revision: https://reviews.llvm.org/D114652
Select SelectionDAG ops smul_lohi/umul_lohi to
v_mad_i64_i32/v_mad_u64_u32 respectively, with an addend of 0.
v_mul_lo, v_mul_hi and v_mad_i64/u64 are all quarter-rate instructions
so it is better to use one instruction than two.
Further improvements are possible to make better use of the addend
operand, but this is already a strict improvement over what we have
now.
Differential Revision: https://reviews.llvm.org/D113986
This patch changes the AMDGPU_Gfx calling convention. It defines the SGPR registers s[4:29] as callee-save and leaves some SGPRs usable for callers. The intention is to avoid unneccessary s_mov instructions for arguments the caller would otherwise save and restore in these registers.
Reviewed By: sebastian-ne
Differential Revision: https://reviews.llvm.org/D111637
Change numBitsSigned to return the minimum size of a signed integer that
can hold the value. This is different by one from the previous result
but is more consistent with numBitsUnsigned. Update all callers. All
callers are now more consistent between the signed and unsigned cases,
and some callers get simpler, especially the ones that deal with
quantities like numBitsSigned(LHS) + numBitsSigned(RHS).
Differential Revision: https://reviews.llvm.org/D112813
Adds legalizer, register bank select, and instruction
select support for G_SBFX and G_UBFX. These opcodes generate
scalar or vector ALU bitfield extract instructions for
AMDGPU. The instructions allow both constant or register
values for the offset and width operands.
The 32-bit scalar version is expanded to a sequence that
combines the offset and width into a single register.
There are no 64-bit vgpr bitfield extract instructions, so the
operations are expanded to a sequence of instructions that
implement the operation. If the width is a constant,
then the 32-bit bitfield extract instructions are used.
Moved the AArch64 specific code for creating G_SBFX to
CombinerHelper.cpp so that it can be used by other targets.
Only bitfield extracts with constant offset and width values
are handled currently.
Differential Revision: https://reviews.llvm.org/D100149
- Take the same principle as the conversion from f64 to i64 with extra
necessary pre- and post-processing. It helps to reduce that conversion
sequence by half compared to legacy one.
Reviewed By: foad
Differential Revision: https://reviews.llvm.org/D104427
Improve the code generation of fp_to_sint
and fp_to_uint for integer on 16-bits.
Differential Revision: https://reviews.llvm.org/D101481
Patch by Julien Pagès!
These were introduced in r279902 on the grounds that using separate
MUL_U24/MUL_I24 and MULHI_U24/MULHI_I24 nodes would introduce multiple
uses of the operands, which would prevent SimplifyDemandedBits from
simplifying the operands.
This has since been fixed by D24672 "AMDGPU/SI: Use new SimplifyDemandedBits helper for multi-use operations"
No functional change intended. At least it has no effect on lit tests.
Differential Revision: https://reviews.llvm.org/D89706
Previously SDNodeFlags::instersectWith(Flags) would do nothing if Flags was
in an undefined state, which is very bad given that this is the default when
getNode() is called without passing an explicit SDNodeFlags argument.
This meant that if an already existing and reused node had a flag which the
second caller to getNode() did not set, that flag would remain uncleared.
This was exposed by https://bugs.llvm.org/show_bug.cgi?id=47092, where an NSW
flag was incorrectly set on an add instruction (which did in fact overflow in
one of the two original contexts), so when SystemZElimCompare removed the
compare with 0 trusting that flag, wrong-code resulted.
There is more that needs to be done in this area as discussed here:
Differential Revision: https://reviews.llvm.org/D86871
Review: Ulrich Weigand, Sanjay Patel
Replace TargetMachine.h include with forward declaration and CodeGen.h include in AMDGPU.h.
Exposes a couple of implicit dependencies that require additional forward declarations/includes.
We have the getNegatibleCost/getNegatedExpression to evaluate the cost and negate the expression.
However, during negating the expression, the cost might change as we are changing the DAG,
and then, hit the assertion if we negated the wrong expression as the cost is not trustful anymore.
This patch is target to remove the getNegatibleCost to avoid the out of sync with getNegatedExpression,
and check the cost during negating the expression. It also reduce the duplicated code between
getNegatibleCost and getNegatedExpression. And fix the crash for the test in D76638
Reviewed By: RKSimon, spatel
Differential Revision: https://reviews.llvm.org/D77319
We have the getNegatibleCost/getNegatedExpression to evaluate the cost and negate the expression.
However, during negating the expression, the cost might change as we are changing the DAG,
and then, hit the assertion if we negated the wrong expression as the cost is not trustful anymore.
This patch is target to remove the getNegatibleCost to avoid the out of sync with getNegatedExpression,
and check the cost during negating the expression. It also reduce the duplicated code between
getNegatibleCost and getNegatedExpression. And fix the crash for the test in D76638
Reviewed By: RKSimon, spatel
Differential Revision: https://reviews.llvm.org/D77319
Interpret these as extending to the next multiple of 32-bits. This had
no effect with i48 for example, which is really split into {i32, i16},
which should extend the high part.
The isNegatibleForFree/getNegatedExpression methods currently rely on a raw char value to indicate whether a negation is beneficial or not.
This patch replaces the char return value with an NegatibleCost enum to more clearly demonstrate what is implied.
It also renames isNegatibleForFree to getNegatibleCost to more accurately reflect whats going on.
Differential Revision: https://reviews.llvm.org/D74221
https://reviews.llvm.org/D72312 introduced an infinite loop which involves
DAGCombiner::visitFMA and AMDGPUTargetLowering::performFNegCombine.
fma( a, fneg(b), fneg(c) ) => fneg( fma (a, b, c) ) => fma( a, fneg(b), fneg(c) ) ...
This only breaks with types where 'isFNegFree' returns flase, e.g. v4f32.
Reproducing the issue also needs the attribute 'no-signed-zeros-fp-math',
and no source mods allowed on one of the users of the Op.
This fix makes changes to indicate that it is not free to negate a fma if it
has users with source mods.
Differential Revision: https://reviews.llvm.org/D73939
Manually select this is as a tablegen workraound. Both SelectionDAG
and GlobalISel end up misplacing the copy to m0 when both instructions
in the output need it. Neither considers that both output instructions
depend on m0. I don't know of any other pattern we need to handle this
case, so it's less effort to just workaround this for now.
I'm mildly worried about potentially reordering exp/exp_done with
IntrWriteMem on the intrinsic.
Requires hacking out the illegal type on SI, so manually select that
case during lowering.
The problem these are supposed to work around can occur before the
intrinsics are lowered into the nodes. Try to directly simplify them
so they are matched before the bit assert operations can be optimized
out.
llvm-svn: 369994
Basically the problem is that X86 doesn't set the Fast flag from
allowsMemoryAccess on certain CPUs due to slow unaligned memory
subtarget features. This prevents bitcasts from being folded into
loads and stores. But all vector loads and stores of the same width
are the same cost on X86.
This patch merges the allowsMemoryAccess call into isLoadBitCastBeneficial to allow X86 to skip it.
Differential Revision: https://reviews.llvm.org/D64295
llvm-svn: 365549
Jay Foad