diff options
| -rw-r--r-- | lib/Transforms/Scalar/LoopStrengthReduce.cpp | 4 | ||||
| -rw-r--r-- | test/CodeGen/X86/lsr-overflow.ll | 26 |
2 files changed, 30 insertions, 0 deletions
diff --git a/lib/Transforms/Scalar/LoopStrengthReduce.cpp b/lib/Transforms/Scalar/LoopStrengthReduce.cpp index dddc65a1d0..9d11876c21 100644 --- a/lib/Transforms/Scalar/LoopStrengthReduce.cpp +++ b/lib/Transforms/Scalar/LoopStrengthReduce.cpp @@ -2112,12 +2112,16 @@ void LSRInstance::GenerateICmpZeroScales(LSRUse &LU, unsigned LUIdx, Formula F = Base; // Check that the multiplication doesn't overflow. + if (F.AM.BaseOffs == INT64_MIN && Factor == -1) + continue; F.AM.BaseOffs = (uint64_t)Base.AM.BaseOffs * Factor; if ((int64_t)F.AM.BaseOffs / Factor != Base.AM.BaseOffs) continue; // Check that multiplying with the use offset doesn't overflow. int64_t Offset = LU.MinOffset; + if (Offset == INT64_MIN && Factor == -1) + continue; Offset = (uint64_t)Offset * Factor; if ((int64_t)Offset / Factor != LU.MinOffset) continue; diff --git a/test/CodeGen/X86/lsr-overflow.ll b/test/CodeGen/X86/lsr-overflow.ll new file mode 100644 index 0000000000..eb6fa905b5 --- /dev/null +++ b/test/CodeGen/X86/lsr-overflow.ll @@ -0,0 +1,26 @@ +; RUN: llc < %s -march=x86-64 | FileCheck %s + +; The comparison uses the pre-inc value, which could lead LSR to +; try to compute -INT64_MIN. + +; CHECK: movabsq $-9223372036854775808, %rax ## imm = 0x8000000000000000 +; CHECK: cmpq %rax, %rbx +; CHECK: sete %al + +declare i64 @bar() + +define i1 @foo() nounwind { +entry: + br label %for.cond.i + +for.cond.i: + %indvar = phi i64 [ 0, %entry ], [ %indvar.next, %for.cond.i ] + %t = call i64 @bar() + %indvar.next = add i64 %indvar, 1 + %s = icmp ne i64 %indvar.next, %t + br i1 %s, label %for.cond.i, label %__ABContainsLabel.exit + +__ABContainsLabel.exit: + %cmp = icmp eq i64 %indvar, 9223372036854775807 + ret i1 %cmp +} |