[llvm] [InstCombine] Fold shift+cttz with power of 2 operands (PR #127055)

[Matthew Devereau via llvm-commits]

================
@@ -103,4 +103,38 @@ entry:
   ret i32 %res
 }
 
+define i64 @fold_cttz_64() vscale_range(1,16) {
+; CHECK-LABEL: define i64 @fold_cttz_64(
+; CHECK-SAME: ) #[[ATTR0:[0-9]+]] {
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    ret i64 4
+;
+entry:
+  %0 = tail call i64 @llvm.vscale.i64()
----------------
MDevereau wrote:

Done

https://github.com/llvm/llvm-project/pull/127055