[llvm] b10e508 - [GVN] Add another test for phi translation miscompile (NFC)
Nikita Popov via llvm-commits
llvm-commits at lists.llvm.org
Wed Aug 31 00:15:21 PDT 2022
Author: Nikita Popov
Date: 2022-08-31T09:14:53+02:00
New Revision: b10e508c19bfb4037be7d78a402c718a889f022d
URL: https://github.com/llvm/llvm-project/commit/b10e508c19bfb4037be7d78a402c718a889f022d
DIFF: https://github.com/llvm/llvm-project/commit/b10e508c19bfb4037be7d78a402c718a889f022d.diff
LOG: [GVN] Add another test for phi translation miscompile (NFC)
Added:
llvm/test/Transforms/GVN/phi-translation-to-wrong-context.ll
Modified:
Removed:
################################################################################
diff --git a/llvm/test/Transforms/GVN/phi-translation-to-wrong-context.ll b/llvm/test/Transforms/GVN/phi-translation-to-wrong-context.ll
new file mode 100644
index 0000000000000..93fc03ae3c06e
--- /dev/null
+++ b/llvm/test/Transforms/GVN/phi-translation-to-wrong-context.ll
@@ -0,0 +1,60 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt -S -gvn < %s | FileCheck %s
+
+; FIXME
+; Phi translation of %gep.j cannot use %gep.i, which is located in a context
+; where %i != 0, and would result in incorrect NoAlias results in a context
+; where %i == 0 may hold.
+
+define i32 @test(i64 %i, i1 %c1, i1 %c2) {
+; CHECK-LABEL: @test(
+; CHECK-NEXT: entry:
+; CHECK-NEXT: [[PTR:%.*]] = alloca [2 x i32], align 4
+; CHECK-NEXT: br i1 [[C1:%.*]], label [[IF:%.*]], label [[ELSE:%.*]]
+; CHECK: if:
+; CHECK-NEXT: br i1 [[C2:%.*]], label [[IF2:%.*]], label [[ELSE2:%.*]]
+; CHECK: if2:
+; CHECK-NEXT: store i32 1, ptr [[PTR]], align 4
+; CHECK-NEXT: br label [[JOIN:%.*]]
+; CHECK: else2:
+; CHECK-NEXT: store i32 2, ptr [[PTR]], align 4
+; CHECK-NEXT: br label [[JOIN]]
+; CHECK: join:
+; CHECK-NEXT: [[J:%.*]] = phi i64 [ [[I:%.*]], [[IF2]] ], [ 0, [[ELSE2]] ]
+; CHECK-NEXT: [[GEP_J:%.*]] = getelementptr inbounds i32, ptr [[PTR]], i64 [[J]]
+; CHECK-NEXT: ret i32 2
+; CHECK: else:
+; CHECK-NEXT: [[CMP:%.*]] = icmp ne i64 [[I]], 0
+; CHECK-NEXT: call void @llvm.assume(i1 [[CMP]])
+; CHECK-NEXT: [[GEP_I:%.*]] = getelementptr inbounds i32, ptr [[PTR]], i64 [[I]]
+; CHECK-NEXT: ret i32 0
+;
+entry:
+ %ptr = alloca [2 x i32]
+ br i1 %c1, label %if, label %else
+
+if:
+ br i1 %c2, label %if2, label %else2
+
+if2:
+ store i32 1, ptr %ptr
+ br label %join
+
+else2:
+ store i32 2, ptr %ptr
+ br label %join
+
+join:
+ %j = phi i64 [ %i, %if2 ], [ 0, %else2 ]
+ %gep.j = getelementptr inbounds i32, ptr %ptr, i64 %j
+ %v = load i32, ptr %gep.j
+ ret i32 %v
+
+else:
+ %cmp = icmp ne i64 %i, 0
+ call void @llvm.assume(i1 %cmp)
+ %gep.i = getelementptr inbounds i32, ptr %ptr, i64 %i
+ ret i32 0
+}
+
+declare void @llvm.assume(i1)
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