[llvm] [Transforms] LoopIdiomRecognize recognize strlen and wcslen (PR #108985)

[Michael Kruse via llvm-commits]

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@@ -0,0 +1,293 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 5
+; RUN: opt -passes='loop-idiom' < %s -S | FileCheck %s
+
+declare void @use(ptr)
+
+define i64 @valid_strlen_1(ptr %0) {
+; CHECK-LABEL: define i64 @valid_strlen_1(
+; CHECK-SAME: ptr [[TMP0:%.*]]) {
+; CHECK-NEXT:    [[STRLEN:%.*]] = call i64 @strlen(ptr [[TMP0]])
+; CHECK-NEXT:    [[DOTLCSSA:%.*]] = getelementptr i8, ptr [[TMP0]], i64 [[STRLEN]]
+; CHECK-NEXT:    br label %[[BB2:.*]]
+; CHECK:       [[BB2]]:
+; CHECK-NEXT:    [[TMP8:%.*]] = icmp eq i8 poison, 0
+; CHECK-NEXT:    [[TMP4:%.*]] = getelementptr inbounds i8, ptr poison, i64 1
+; CHECK-NEXT:    br i1 true, label %[[BB5:.*]], label %[[BB2]]
+; CHECK:       [[BB5]]:
+; CHECK-NEXT:    [[TMP12:%.*]] = ptrtoint ptr [[DOTLCSSA]] to i64
+; CHECK-NEXT:    [[TMP13:%.*]] = ptrtoint ptr [[TMP0]] to i64
+; CHECK-NEXT:    [[TMP14:%.*]] = sub i64 [[TMP12]], [[TMP13]]
+; CHECK-NEXT:    ret i64 [[TMP14]]
+;
+  br label %2
+
+2:                                                ; preds = %2, %1
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Meinersbur wrote:

Could you run `opt -passes=instnamer -S` over the file? This often helps with tracking the origin of an instruction when FileCheck fails.

https://github.com/llvm/llvm-project/pull/108985