Update InstCombineShifts.cpp

houngkoungting · web-flow · commit 69c1f2776efc · 2025-03-15T23:14:33.000+08:00
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineShifts.cpp b/llvm/lib/Transforms/InstCombine/InstCombineShifts.cpp
@@ -994,6 +994,11 @@ static bool setShiftFlags(BinaryOperator &I, const SimplifyQuery &Q) {
       I.setIsExact();
       return true;
     }
+      // shr X, cttz(X)
+    if (match(I.getOperand(1), m_Intrinsic<Intrinsic::cttz>(m_Specific(I.getOperand(0))))) {
+      I.setIsExact();
+      return true;
+    }
   }
 
   // Compute what we know about shift count.

Original file line number	Diff line number	Diff line change
`@@ -994,6 +994,11 @@ static bool setShiftFlags(BinaryOperator &I, const SimplifyQuery &Q) {`
`994`	`994`	`I.setIsExact();`
`995`	`995`	`return true;`
`996`	`996`	`}`
	`997`	`+ // shr X, cttz(X)`
	`998`	`+ if (match(I.getOperand(1), m_Intrinsic<Intrinsic::cttz>(m_Specific(I.getOperand(0))))) {`
	`999`	`+ I.setIsExact();`
	`1000`	`+ return true;`
	`1001`	`+ }`
`997`	`1002`	`}`
`998`	`1003`
`999`	`1004`	`// Compute what we know about shift count.`