[llvm] abf29d9 - [InstCombine] visitAnd - use m_SpecificInt instead of m_APInt + comparison. NFCI.

[Simon Pilgrim via llvm-commits]

Author: Simon Pilgrim
Date: 2020-11-17T17:37:10Z
New Revision: abf29d9862d898c02f3df95cbdc4e9bdba396b6f

URL: https://github.com/llvm/llvm-project/commit/abf29d9862d898c02f3df95cbdc4e9bdba396b6f
DIFF: https://github.com/llvm/llvm-project/commit/abf29d9862d898c02f3df95cbdc4e9bdba396b6f.diff

LOG: [InstCombine] visitAnd - use m_SpecificInt instead of m_APInt + comparison. NFCI.

m_SpecificInt has the same 'no undef element' behaviour as m_APInt so no change there, and anyway we have test coverage for undef elements in the fold.

Noticed while fixing a Wshadow warning about shadow Value *X, *Y variables.

Added: 
    

Modified: 
    llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp

Removed: 
    


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diff  --git a/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp b/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
index e9f9f4dcb535..bb8ace29931a 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
@@ -1962,16 +1962,12 @@ Instruction *InstCombinerImpl::visitAnd(BinaryOperator &I) {
     return SelectInst::Create(A, Op0, Constant::getNullValue(Ty));
 
   // and(ashr(subNSW(Y, X), ScalarSizeInBits(Y)-1), X) --> X s> Y ? X : 0.
-  {
-    Value *X, *Y;
-    const APInt *ShAmt;
-    if (match(&I, m_c_And(m_OneUse(m_AShr(m_NSWSub(m_Value(Y), m_Value(X)),
-                                          m_APInt(ShAmt))),
-                          m_Deferred(X))) &&
-        *ShAmt == Ty->getScalarSizeInBits() - 1) {
-      Value *NewICmpInst = Builder.CreateICmpSGT(X, Y);
-      return SelectInst::Create(NewICmpInst, X, ConstantInt::getNullValue(Ty));
-    }
+  if (match(&I, m_c_And(m_OneUse(m_AShr(
+                            m_NSWSub(m_Value(Y), m_Value(X)),
+                            m_SpecificInt(Ty->getScalarSizeInBits() - 1))),
+                        m_Deferred(X)))) {
+    Value *NewICmpInst = Builder.CreateICmpSGT(X, Y);
+    return SelectInst::Create(NewICmpInst, X, ConstantInt::getNullValue(Ty));
   }
 
   return nullptr;