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[AArch64][SVE] Fix crash for DestructiveBinaryCommWithRev zero merging
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Address more Destructive type according the review on D141471

* DestructiveUnaryPassthru and DestructiveBinaryImm always return true, don't need fix
* DestructiveTernaryCommWithRev may also return false, but now don't define FalseLanesZero in the backend codegen

Reviewed By: paulwalker-arm

Differential Revision: https://reviews.llvm.org/D142978
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vfdff committed Feb 7, 2023
1 parent 39af465 commit 341b1df
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Showing 2 changed files with 45 additions and 2 deletions.
6 changes: 4 additions & 2 deletions llvm/lib/Target/AArch64/AArch64ExpandPseudoInsts.cpp
Expand Up @@ -589,7 +589,8 @@ bool AArch64ExpandPseudo::expand_DestructiveOp(
// If we cannot prefix the requested instruction we'll instead emit a
// prefixed_zeroing_mov for DestructiveBinary.
assert((DOPRegIsUnique || DType == AArch64::DestructiveBinary ||
DType == AArch64::DestructiveBinaryComm) &&
DType == AArch64::DestructiveBinaryComm ||
DType == AArch64::DestructiveBinaryCommWithRev) &&
"The destructive operand should be unique");
assert(ElementSize != AArch64::ElementSizeNone &&
"This instruction is unpredicated");
Expand All @@ -607,7 +608,8 @@ bool AArch64ExpandPseudo::expand_DestructiveOp(
// unique. Zeros the lanes in z0 that aren't active in p0 with sequence
// movprfx z0.b, p0/z, z0.b; lsl z0.b, p0/m, z0.b, #0;
if ((DType == AArch64::DestructiveBinary ||
DType == AArch64::DestructiveBinaryComm) &&
DType == AArch64::DestructiveBinaryComm ||
DType == AArch64::DestructiveBinaryCommWithRev) &&
!DOPRegIsUnique) {
BuildMI(MBB, MBBI, MI.getDebugLoc(), TII->get(LSLZero))
.addReg(DstReg, RegState::Define)
Expand Down
@@ -0,0 +1,41 @@
# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py
# RUN: llc -mtriple=aarch64 -mattr=+sve -mattr=+use-experimental-zeroing-pseudos -run-pass=aarch64-expand-pseudo %s -o - | FileCheck %s

# Should create an additional LSL to zero the lanes as the DstReg is not unique

--- |
define <vscale x 4 x float> @fsub_s_zero(<vscale x 4 x i1> %pg, <vscale x 4 x float> %a){
%a_z = select <vscale x 4 x i1> %pg, <vscale x 4 x float> %a, <vscale x 4 x float> zeroinitializer
%out = call <vscale x 4 x float> @llvm.aarch64.sve.fsub.nxv4f32(<vscale x 4 x i1> %pg,
<vscale x 4 x float> %a_z,
<vscale x 4 x float> %a_z)
ret <vscale x 4 x float> %out
}

declare <vscale x 4 x float> @llvm.aarch64.sve.fsub.nxv4f32(<vscale x 4 x i1>, <vscale x 4 x float>, <vscale x 4 x float>)
...
---
name: fsub_s_zero
alignment: 4
tracksRegLiveness: true
tracksDebugUserValues: true
registers: []
liveins:
- { reg: '$p0', virtual-reg: '' }
- { reg: '$z0', virtual-reg: '' }
body: |
bb.0 (%ir-block.0):
liveins: $p0, $z0
; CHECK-LABEL: name: fsub_s_zero
; CHECK: liveins: $p0, $z0
; CHECK-NEXT: {{ $}}
; CHECK-NEXT: BUNDLE implicit-def $z0, implicit-def $q0, implicit-def $d0, implicit-def $s0, implicit-def $h0, implicit-def $b0, implicit-def $z0_hi, implicit $p0, implicit $z0 {
; CHECK-NEXT: $z0 = MOVPRFX_ZPzZ_S $p0, $z0
; CHECK-NEXT: $z0 = LSL_ZPmI_S renamable $p0, internal $z0, 0
; CHECK-NEXT: $z0 = FSUBR_ZPmZ_S renamable $p0, internal killed $z0, internal killed renamable $z0
; CHECK-NEXT: }
; CHECK-NEXT: RET undef $lr, implicit $z0
renamable $z0 = nnan ninf nsz arcp contract afn reassoc FSUB_ZPZZ_ZERO_S renamable $p0, killed renamable $z0, renamable $z0
RET_ReallyLR implicit $z0
...

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