[llvm] [ARM][MVE] Remove kill flags when reusing VPR register. (PR #86300)
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Fri Mar 22 09:05:26 PDT 2024
llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-backend-arm
Author: David Green (davemgreen)
<details>
<summary>Changes</summary>
The vpr register may no longer be killed where it was, so we should be removing the kill flags.
---
Full diff: https://github.com/llvm/llvm-project/pull/86300.diff
2 Files Affected:
- (modified) llvm/lib/Target/ARM/MVETPAndVPTOptimisationsPass.cpp (+1)
- (modified) llvm/test/CodeGen/Thumb2/mve-vpt-optimisations.mir (+24-1)
``````````diff
diff --git a/llvm/lib/Target/ARM/MVETPAndVPTOptimisationsPass.cpp b/llvm/lib/Target/ARM/MVETPAndVPTOptimisationsPass.cpp
index 5c113ccfdc1579..e8d2cba7ee556f 100644
--- a/llvm/lib/Target/ARM/MVETPAndVPTOptimisationsPass.cpp
+++ b/llvm/lib/Target/ARM/MVETPAndVPTOptimisationsPass.cpp
@@ -958,6 +958,7 @@ bool MVETPAndVPTOptimisations::ReplaceConstByVPNOTs(MachineBasicBlock &MBB,
unsigned NotImm = ~Imm & 0xffff;
if (LastVPTReg != 0 && LastVPTReg != VPR && LastVPTImm == Imm) {
+ MRI->clearKillFlags(LastVPTReg);
Instr.getOperand(PIdx + 1).setReg(LastVPTReg);
if (MRI->use_empty(VPR)) {
DeadInstructions.insert(Copy);
diff --git a/llvm/test/CodeGen/Thumb2/mve-vpt-optimisations.mir b/llvm/test/CodeGen/Thumb2/mve-vpt-optimisations.mir
index f28311e6563f41..f9b175ed80fbf3 100644
--- a/llvm/test/CodeGen/Thumb2/mve-vpt-optimisations.mir
+++ b/llvm/test/CodeGen/Thumb2/mve-vpt-optimisations.mir
@@ -1,5 +1,5 @@
# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py
-# RUN: llc -mtriple=thumbv8.1m.main-none-none-eabi -mattr=+armv8.1-m.main,+hwdiv,+mve.fp,+ras,+thumb-mode -run-pass arm-mve-vpt-opts %s -o - | FileCheck %s
+# RUN: llc -mtriple=thumbv8.1m.main-none-none-eabi -mattr=+armv8.1-m.main,+hwdiv,+mve.fp,+ras,+thumb-mode -run-pass arm-mve-vpt-opts -verify-machineinstrs %s -o - | FileCheck %s
---
name: vcmp_with_opposite_cond
@@ -1021,3 +1021,26 @@ body: |
%16:mqpr = MVE_VORR %15, %15, 1, %10, $noreg, undef %16
%17:mqpr = MVE_VORR %16, %16, 1, %11, $noreg, undef %17
...
+---
+name: reuse_kill_flags
+alignment: 4
+body: |
+ bb.0:
+ ; CHECK-LABEL: name: reuse_kill_flags
+ ; CHECK: [[t2MOVi:%[0-9]+]]:tgpreven = t2MOVi 0, 14 /* CC::al */, $noreg, $noreg
+ ; CHECK-NEXT: [[COPY:%[0-9]+]]:vccr = COPY [[t2MOVi]]
+ ; CHECK-NEXT: [[DEF:%[0-9]+]]:mqpr = IMPLICIT_DEF
+ ; CHECK-NEXT: [[MVE_VORR:%[0-9]+]]:mqpr = MVE_VORR [[DEF]], [[DEF]], 1, [[COPY]], $noreg, undef [[MVE_VORR]]
+ ; CHECK-NEXT: [[DEF1:%[0-9]+]]:mqpr = IMPLICIT_DEF
+ ; CHECK-NEXT: [[MVE_VORR1:%[0-9]+]]:mqpr = MVE_VORR [[DEF1]], [[DEF1]], 1, killed [[COPY]], $noreg, undef [[MVE_VORR1]]
+ ; CHECK-NEXT: tBX_RET 14 /* CC::al */, $noreg, implicit [[DEF1]]
+ %0:tgpreven = t2MOVi 0, 14, $noreg, $noreg
+ %1:vccr = COPY %0:tgpreven
+ %2:mqpr = IMPLICIT_DEF
+ %3:mqpr = MVE_VORR %2:mqpr, %2:mqpr, 1, killed %1, $noreg, undef %3
+ %4:vccr = COPY %0:tgpreven
+ %5:mqpr = IMPLICIT_DEF
+ %6:mqpr = MVE_VORR %5:mqpr, %5:mqpr, 1, killed %4, $noreg, undef %6
+ tBX_RET 14 /* CC::al */, $noreg, implicit %5:mqpr
+
+...
``````````
</details>
https://github.com/llvm/llvm-project/pull/86300
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