[llvm] [ValueTracking] Use isSafeToSpeculativelyExecuteWithVariableReplaced() in more places (PR #109149)

[Nikita Popov via llvm-commits]

https://github.com/nikic created https://github.com/llvm/llvm-project/pull/109149

This replaces some uses of isSafeToSpeculativelyExecute() with isSafeToSpeculativelyExecuteWithVariableReplaced(), in cases where we are guarding against operand changes rather plain speculation.

I believe that this is NFC with the current implementation of the function (as it only does something different from loads), but this makes us more defensive against future generalizations.

>From c1f69c1ffb265a228f5540f6e271ca349aec4d8e Mon Sep 17 00:00:00 2001
From: Nikita Popov <npopov at redhat.com>
Date: Wed, 18 Sep 2024 16:22:27 +0200
Subject: [PATCH] [ValueTracking] Use
 isSafeToSpeculativelyExecuteWithVariableReplaced() in more places

This replaces some uses of isSafeToSpeculativelyExecute() with
isSafeToSpeculativelyExecuteWithVariableReplaced(), in cases where
we are guarding against operand changes rather plain speculation.

I believe that this is NFC with the current implementation of the
function (as it only does something different from loads), but
this makes us more defensive against future generalizations.
---
 llvm/lib/Analysis/LazyValueInfo.cpp                      | 3 ++-
 llvm/lib/Transforms/InstCombine/InstCombineVectorOps.cpp | 5 +++--
 llvm/lib/Transforms/InstCombine/InstructionCombining.cpp | 2 +-
 3 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/llvm/lib/Analysis/LazyValueInfo.cpp b/llvm/lib/Analysis/LazyValueInfo.cpp
index 69e0627a89cc29..30dc4ae30dbfa5 100644
--- a/llvm/lib/Analysis/LazyValueInfo.cpp
+++ b/llvm/lib/Analysis/LazyValueInfo.cpp
@@ -1572,7 +1572,8 @@ ValueLatticeElement LazyValueInfoImpl::getValueAtUse(const Use &U) {
     // This also disallows looking through phi nodes: If the phi node is part
     // of a cycle, we might end up reasoning about values from different cycle
     // iterations (PR60629).
-    if (!CurrI->hasOneUse() || !isSafeToSpeculativelyExecute(CurrI))
+    if (!CurrI->hasOneUse() ||
+        !isSafeToSpeculativelyExecuteWithVariableReplaced(CurrI))
       break;
     CurrU = &*CurrI->use_begin();
   }
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineVectorOps.cpp b/llvm/lib/Transforms/InstCombine/InstCombineVectorOps.cpp
index e018f80dc3b2c8..d9b4faff4c004d 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineVectorOps.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineVectorOps.cpp
@@ -476,7 +476,8 @@ Instruction *InstCombinerImpl::visitExtractElementInst(ExtractElementInst &EI) {
   // it may make the operand poison.
   BinaryOperator *BO;
   if (match(SrcVec, m_BinOp(BO)) && cheapToScalarize(SrcVec, Index) &&
-      (HasKnownValidIndex || isSafeToSpeculativelyExecute(BO))) {
+      (HasKnownValidIndex ||
+       isSafeToSpeculativelyExecuteWithVariableReplaced(BO))) {
     // extelt (binop X, Y), Index --> binop (extelt X, Index), (extelt Y, Index)
     Value *X = BO->getOperand(0), *Y = BO->getOperand(1);
     Value *E0 = Builder.CreateExtractElement(X, Index);
@@ -2777,7 +2778,7 @@ Instruction *InstCombinerImpl::simplifyBinOpSplats(ShuffleVectorInst &SVI) {
     return nullptr;
 
   auto *BinOp = cast<BinaryOperator>(Op0);
-  if (!isSafeToSpeculativelyExecute(BinOp))
+  if (!isSafeToSpeculativelyExecuteWithVariableReplaced(BinOp))
     return nullptr;
 
   Value *NewBO = Builder.CreateBinOp(BinOp->getOpcode(), X, Y);
diff --git a/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp b/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
index aa3f3fbdaeffa0..1e606c51f72cdb 100644
--- a/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
@@ -2105,7 +2105,7 @@ Instruction *InstCombinerImpl::foldVectorBinop(BinaryOperator &Inst) {
   // It may not be safe to reorder shuffles and things like div, urem, etc.
   // because we may trap when executing those ops on unknown vector elements.
   // See PR20059.
-  if (!isSafeToSpeculativelyExecute(&Inst))
+  if (!isSafeToSpeculativelyExecuteWithVariableReplaced(&Inst))
     return nullptr;
 
   auto createBinOpShuffle = [&](Value *X, Value *Y, ArrayRef<int> M) {