[InstSimplify][InstCombine] Remove unnecessary m_c_* matchers.

[dtcxzyw]

This patch removes unnecessary m_c_* matchers since we always canonicalize commutive_op Cst, X into commutive_op X, Cst.

Compile-time impact: https://llvm-compile-time-tracker.com/compare.php?from=bfc0b7c6891896ee8e9818f22800472510093864&to=d27b058bb9acaa43d3cadbf3cd889e8f79e5c634&stat=instructions:u

[llvmbot]

@llvm/pr-subscribers-llvm-ir
@llvm/pr-subscribers-llvm-analysis

@llvm/pr-subscribers-llvm-transforms

Author: Yingwei Zheng (dtcxzyw)

Changes

This patch removes unnecessary m_c_* matchers since we always canonicalize commutive_op Cst, X into commutive_op X, Cst.

Compile-time impact: https://llvm-compile-time-tracker.com/compare.php?from=bfc0b7c6891896ee8e9818f22800472510093864&to=d27b058bb9acaa43d3cadbf3cd889e8f79e5c634&stat=instructions:u

---

Full diff: https://github.com/llvm/llvm-project/pull/81712.diff

6 Files Affected:

• (modified) llvm/lib/Analysis/IVDescriptors.cpp (+1-1)
• (modified) llvm/lib/Analysis/InstructionSimplify.cpp (+2-2)
• (modified) llvm/lib/IR/IntrinsicInst.cpp (+1-1)
• (modified) llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp (+1-1)
• (modified) llvm/lib/Transforms/InstCombine/InstCombineNegator.cpp (+3-3)
• (modified) llvm/test/Transforms/InstSimplify/compare.ll (-30)

diff --git a/llvm/lib/Analysis/IVDescriptors.cpp b/llvm/lib/Analysis/IVDescriptors.cpp
index 1aa324c6b5f380..055f121e743411 100644
--- a/llvm/lib/Analysis/IVDescriptors.cpp
+++ b/llvm/lib/Analysis/IVDescriptors.cpp
@@ -76,7 +76,7 @@ static Instruction *lookThroughAnd(PHINode *Phi, Type *&RT,
 
   // Matches either I & 2^x-1 or 2^x-1 & I. If we find a match, we update RT
   // with a new integer type of the corresponding bit width.
-  if (match(J, m_c_And(m_Instruction(I), m_APInt(M)))) {
+  if (match(J, m_And(m_Instruction(I), m_APInt(M)))) {
     int32_t Bits = (*M + 1).exactLogBase2();
     if (Bits > 0) {
       RT = IntegerType::get(Phi->getContext(), Bits);
diff --git a/llvm/lib/Analysis/InstructionSimplify.cpp b/llvm/lib/Analysis/InstructionSimplify.cpp
index 51e258d69e9e2e..2d72a032a6c6d5 100644
--- a/llvm/lib/Analysis/InstructionSimplify.cpp
+++ b/llvm/lib/Analysis/InstructionSimplify.cpp
@@ -3246,8 +3246,8 @@ static bool trySimplifyICmpWithAdds(CmpInst::Predicate Pred, Value *LHS,
 
   Value *X;
   const APInt *C1, *C2;
-  if (!match(LHS, m_c_Add(m_Value(X), m_APInt(C1))) ||
-      !match(RHS, m_c_Add(m_Specific(X), m_APInt(C2))))
+  if (!match(LHS, m_Add(m_Value(X), m_APInt(C1))) ||
+      !match(RHS, m_Add(m_Specific(X), m_APInt(C2))))
     return false;
 
   return (C1->slt(*C2) && C1->isNonNegative()) ||
diff --git a/llvm/lib/IR/IntrinsicInst.cpp b/llvm/lib/IR/IntrinsicInst.cpp
index 7a3b708e740067..5050091836b7f9 100644
--- a/llvm/lib/IR/IntrinsicInst.cpp
+++ b/llvm/lib/IR/IntrinsicInst.cpp
@@ -623,7 +623,7 @@ bool VPIntrinsic::canIgnoreVectorLengthParam() const {
   if (EC.isScalable()) {
     // Compare vscale patterns
     uint64_t VScaleFactor;
-    if (match(VLParam, m_c_Mul(m_ConstantInt(VScaleFactor), m_VScale())))
+    if (match(VLParam, m_Mul(m_VScale(), m_ConstantInt(VScaleFactor))))
       return VScaleFactor >= EC.getKnownMinValue();
     return (EC.getKnownMinValue() == 1) && match(VLParam, m_VScale());
   }
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp b/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
index 4465eb8992fbbf..0af9a2786f6901 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
@@ -4450,7 +4450,7 @@ Instruction *InstCombinerImpl::foldNot(BinaryOperator &I) {
     }
 
     // ~(X + C) --> ~C - X
-    if (match(NotVal, m_c_Add(m_Value(X), m_ImmConstant(C))))
+    if (match(NotVal, m_Add(m_Value(X), m_ImmConstant(C))))
       return BinaryOperator::CreateSub(ConstantExpr::getNot(C), X);
 
     // ~(X - Y) --> ~X + Y
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineNegator.cpp b/llvm/lib/Transforms/InstCombine/InstCombineNegator.cpp
index 62e49469cb0198..f73679f9461bad 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineNegator.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineNegator.cpp
@@ -258,9 +258,9 @@ std::array<Value *, 2> Negator::getSortedOperandsOfBinOp(Instruction *I) {
   case Instruction::And: {
     Constant *ShAmt;
     // sub(y,and(lshr(x,C),1)) --> add(ashr(shl(x,(BW-1)-C),BW-1),y)
-    if (match(I, m_c_And(m_OneUse(m_TruncOrSelf(
-                             m_LShr(m_Value(X), m_ImmConstant(ShAmt)))),
-                         m_One()))) {
+    if (match(I, m_And(m_OneUse(m_TruncOrSelf(
+                           m_LShr(m_Value(X), m_ImmConstant(ShAmt)))),
+                       m_One()))) {
       unsigned BW = X->getType()->getScalarSizeInBits();
       Constant *BWMinusOne = ConstantInt::get(X->getType(), BW - 1);
       Value *R = Builder.CreateShl(X, Builder.CreateSub(BWMinusOne, ShAmt));
diff --git a/llvm/test/Transforms/InstSimplify/compare.ll b/llvm/test/Transforms/InstSimplify/compare.ll
index ac2ebf52ed6296..1e90f0edbd8003 100644
--- a/llvm/test/Transforms/InstSimplify/compare.ll
+++ b/llvm/test/Transforms/InstSimplify/compare.ll
@@ -2453,36 +2453,6 @@ define i1 @icmp_nsw_2(i32 %V) {
   ret i1 %cmp
 }
 
-define i1 @icmp_nsw_commute(i32 %V) {
-; CHECK-LABEL: @icmp_nsw_commute(
-; CHECK-NEXT:    ret i1 true
-;
-  %add5 = add i32 5, %V
-  %add6 = add nsw i32 %V, 6
-  %cmp = icmp slt i32 %add5, %add6
-  ret i1 %cmp
-}
-
-define i1 @icmp_nsw_commute2(i32 %V) {
-; CHECK-LABEL: @icmp_nsw_commute2(
-; CHECK-NEXT:    ret i1 true
-;
-  %add5 = add i32 %V, 5
-  %add6 = add nsw i32 6, %V
-  %cmp = icmp slt i32 %add5, %add6
-  ret i1 %cmp
-}
-
-define i1 @icmp_nsw_commute3(i32 %V) {
-; CHECK-LABEL: @icmp_nsw_commute3(
-; CHECK-NEXT:    ret i1 true
-;
-  %add5 = add i32 5, %V
-  %add6 = add nsw i32 6, %V
-  %cmp = icmp slt i32 %add5, %add6
-  ret i1 %cmp
-}
-
 define i1 @icmp_nsw_22(i32 %V) {
 ; CHECK-LABEL: @icmp_nsw_22(
 ; CHECK-NEXT:    ret i1 true

[nikic]

LGTM

[nikic]

(Shouldn't mark this as NFC though, as it does change optimization behavior for InstSimplify.)

[arsenm]

I'd expect the InstSimplify uses to stay as they are?

[nikic]

We only handle non-canonical patterns in InstSimplify if there is phase-ordering justification to do so, which is absent here. I did check the original review to confirm that this was done simply "because we can" and not for a specific reason.