[PATCH] D108734: [InstCombine] Replace icmp invariant group operands with the invariant group's operands

[Arthur Eubanks via Phabricator via llvm-commits]

aeubanks updated this revision to Diff 368976.
aeubanks added a comment.

only optimize null comparisons


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D108734/new/

https://reviews.llvm.org/D108734

Files:
  llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
  llvm/test/Transforms/InstCombine/invariant.group.ll


Index: llvm/test/Transforms/InstCombine/invariant.group.ll
===================================================================
--- llvm/test/Transforms/InstCombine/invariant.group.ll
+++ llvm/test/Transforms/InstCombine/invariant.group.ll
@@ -161,8 +161,7 @@
 
 define i1 @icmp_launder(i8* %a) {
 ; CHECK-LABEL: @icmp_launder(
-; CHECK-NEXT:    [[A2:%.*]] = call i8* @llvm.launder.invariant.group.p0i8(i8* [[A:%.*]])
-; CHECK-NEXT:    [[R:%.*]] = icmp eq i8* [[A2]], null
+; CHECK-NEXT:    [[R:%.*]] = icmp eq i8* [[A:%.*]], null
 ; CHECK-NEXT:    ret i1 [[R]]
 ;
   %a2 = call i8* @llvm.launder.invariant.group.p0i8(i8* %a)
@@ -172,8 +171,7 @@
 
 define i1 @icmp_strip(i8* %a) {
 ; CHECK-LABEL: @icmp_strip(
-; CHECK-NEXT:    [[A2:%.*]] = call i8* @llvm.strip.invariant.group.p0i8(i8* [[A:%.*]])
-; CHECK-NEXT:    [[R:%.*]] = icmp eq i8* [[A2]], null
+; CHECK-NEXT:    [[R:%.*]] = icmp eq i8* [[A:%.*]], null
 ; CHECK-NEXT:    ret i1 [[R]]
 ;
   %a2 = call i8* @llvm.strip.invariant.group.p0i8(i8* %a)
@@ -206,8 +204,7 @@
 ; Check that null always becomes the RHS
 define i1 @icmp_launder_lhs(i8* %a) {
 ; CHECK-LABEL: @icmp_launder_lhs(
-; CHECK-NEXT:    [[A2:%.*]] = call i8* @llvm.launder.invariant.group.p0i8(i8* [[A:%.*]])
-; CHECK-NEXT:    [[R:%.*]] = icmp eq i8* [[A2]], null
+; CHECK-NEXT:    [[R:%.*]] = icmp eq i8* [[A:%.*]], null
 ; CHECK-NEXT:    ret i1 [[R]]
 ;
   %a2 = call i8* @llvm.launder.invariant.group.p0i8(i8* %a)
Index: llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
===================================================================
--- llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
+++ llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
@@ -5702,6 +5702,23 @@
   return ExtractValueInst::Create(UAddOv, 1);
 }
 
+static Instruction *foldICmpInvariantGroup(ICmpInst &I) {
+  if (!I.getOperand(0)->getType()->isPointerTy() ||
+      NullPointerIsDefined(
+          I.getParent()->getParent(),
+          I.getOperand(0)->getType()->getPointerAddressSpace())) {
+    return nullptr;
+  }
+  Instruction *Op;
+  if (match(I.getOperand(0), m_Instruction(Op)) &&
+      match(I.getOperand(1), m_Zero())) {
+    if (Op->isLaunderOrStripInvariantGroup())
+      return ICmpInst::Create(Instruction::ICmp, I.getPredicate(),
+                              Op->getOperand(0), I.getOperand(1));
+  }
+  return nullptr;
+}
+
 Instruction *InstCombinerImpl::visitICmpInst(ICmpInst &I) {
   bool Changed = false;
   const SimplifyQuery Q = SQ.getWithInstruction(&I);
@@ -5942,6 +5959,9 @@
     if (Instruction *Res = foldVectorCmp(I, Builder))
       return Res;
 
+  if (Instruction *Res = foldICmpInvariantGroup(I))
+    return Res;
+
   return Changed ? &I : nullptr;
 }
 


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