[llvm] 2938f9b - [InstCombine] Fix worklist management in select value equiv fold (NFCI)

[Nikita Popov via llvm-commits]

Author: Nikita Popov
Date: 2023-05-23T16:37:56+02:00
New Revision: 2938f9b46f0de8aec89b57eb1cd343745cfeb161

URL: https://github.com/llvm/llvm-project/commit/2938f9b46f0de8aec89b57eb1cd343745cfeb161
DIFF: https://github.com/llvm/llvm-project/commit/2938f9b46f0de8aec89b57eb1cd343745cfeb161.diff

LOG: [InstCombine] Fix worklist management in select value equiv fold (NFCI)

Requeue the modified instruction.

This should be NFC apart from worklist order effects.

Added: 
    

Modified: 
    llvm/lib/Transforms/InstCombine/InstCombineInternal.h
    llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
    llvm/test/Transforms/InstCombine/select-binop-cmp.ll

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Transforms/InstCombine/InstCombineInternal.h b/llvm/lib/Transforms/InstCombine/InstCombineInternal.h
index fcf777d0b31e..2486be77ebab 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineInternal.h
+++ b/llvm/lib/Transforms/InstCombine/InstCombineInternal.h
@@ -636,6 +636,8 @@ class LLVM_LIBRARY_VISIBILITY InstCombinerImpl final
                             SelectPatternFlavor SPF2, Value *C);
   Instruction *foldSelectInstWithICmp(SelectInst &SI, ICmpInst *ICI);
   Instruction *foldSelectValueEquivalence(SelectInst &SI, ICmpInst &ICI);
+  bool replaceInInstruction(Value *V, Value *Old, Value *New,
+                            unsigned Depth = 0);
 
   Value *insertRangeTest(Value *V, const APInt &Lo, const APInt &Hi,
                          bool isSigned, bool Inside);

diff  --git a/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp b/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
index ca75fcfaee3a..1b2930433809 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
@@ -1238,8 +1238,8 @@ static Instruction *canonicalizeSPF(SelectInst &Sel, ICmpInst &Cmp,
   return nullptr;
 }
 
-static bool replaceInInstruction(Value *V, Value *Old, Value *New,
-                                 InstCombiner &IC, unsigned Depth = 0) {
+bool InstCombinerImpl::replaceInInstruction(Value *V, Value *Old, Value *New,
+                                            unsigned Depth) {
   // Conservatively limit replacement to two instructions upwards.
   if (Depth == 2)
     return false;
@@ -1251,10 +1251,11 @@ static bool replaceInInstruction(Value *V, Value *Old, Value *New,
   bool Changed = false;
   for (Use &U : I->operands()) {
     if (U == Old) {
-      IC.replaceUse(U, New);
+      replaceUse(U, New);
+      Worklist.add(I);
       Changed = true;
     } else {
-      Changed |= replaceInInstruction(U, Old, New, IC, Depth + 1);
+      Changed |= replaceInInstruction(U, Old, New, Depth + 1);
     }
   }
   return Changed;
@@ -1310,7 +1311,7 @@ Instruction *InstCombinerImpl::foldSelectValueEquivalence(SelectInst &Sel,
     // FIXME: Support vectors.
     if (match(CmpRHS, m_ImmConstant()) && !match(CmpLHS, m_ImmConstant()) &&
         !Cmp.getType()->isVectorTy())
-      if (replaceInInstruction(TrueVal, CmpLHS, CmpRHS, *this))
+      if (replaceInInstruction(TrueVal, CmpLHS, CmpRHS))
         return &Sel;
   }
   if (TrueVal != CmpRHS &&

diff  --git a/llvm/test/Transforms/InstCombine/select-binop-cmp.ll b/llvm/test/Transforms/InstCombine/select-binop-cmp.ll
index 8a20b09c2990..52248928e240 100644
--- a/llvm/test/Transforms/InstCombine/select-binop-cmp.ll
+++ b/llvm/test/Transforms/InstCombine/select-binop-cmp.ll
@@ -1,5 +1,5 @@
 ; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
-; RUN: opt < %s -passes=instcombine -S | FileCheck %s
+; RUN: opt < %s -passes=instcombine -instcombine-infinite-loop-threshold=2 -S | FileCheck %s
 
 declare void @use(<2 x i1>)
 declare void @use2(i1)