diff options
| author | Tom Stellard <tstellar@redhat.com> | 2020-05-09 00:34:05 +0000 |
|---|---|---|
| committer | Tom Stellard <tstellar@redhat.com> | 2020-06-23 18:45:59 -0700 |
| commit | be4501f6e487fc27b242e0799cfeed3b4eedc4cd (patch) | |
| tree | 3503f839ef829602339d4fa290c4e13ea4a90eda | |
| parent | 28a6713e107c9f878cb6c59db8548bb732dcc79d (diff) | |
| download | bcm5719-llvm-be4501f6e487fc27b242e0799cfeed3b4eedc4cd.tar.gz bcm5719-llvm-be4501f6e487fc27b242e0799cfeed3b4eedc4cd.zip | |
[InstCombine] prevent infinite loop with sub/abs of constant expression
PR45539:
https://bugs.llvm.org/show_bug.cgi?id=45539
(cherry picked from commit 01bcc3e9371470e1974f066ced353df15e10056d)
| -rw-r--r-- | llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp | 2 | ||||
| -rw-r--r-- | llvm/test/Transforms/InstCombine/abs-1.ll | 18 |
2 files changed, 19 insertions, 1 deletions
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp b/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp index ec976a971e3..23561c25c50 100644 --- a/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp +++ b/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp @@ -1768,7 +1768,7 @@ Instruction *InstCombiner::visitSub(BinaryOperator &I) { Constant *C2; // C-(C2-X) --> X+(C-C2) - if (match(Op1, m_Sub(m_Constant(C2), m_Value(X)))) + if (match(Op1, m_Sub(m_Constant(C2), m_Value(X))) && !isa<ConstantExpr>(C2)) return BinaryOperator::CreateAdd(X, ConstantExpr::getSub(C, C2)); // C-(X+C2) --> (C-C2)-X diff --git a/llvm/test/Transforms/InstCombine/abs-1.ll b/llvm/test/Transforms/InstCombine/abs-1.ll index 2b23953497b..42ee67e530e 100644 --- a/llvm/test/Transforms/InstCombine/abs-1.ll +++ b/llvm/test/Transforms/InstCombine/abs-1.ll @@ -569,3 +569,21 @@ define i1 @abs_must_be_positive(i32 %x) { ret i1 %c2 } +@g = external global i64 + +; PR45539 - https://bugs.llvm.org/show_bug.cgi?id=45539 + +define i64 @infinite_loop_constant_expression_abs(i64 %arg) { +; CHECK-LABEL: @infinite_loop_constant_expression_abs( +; CHECK-NEXT: [[T:%.*]] = sub i64 ptrtoint (i64* @g to i64), [[ARG:%.*]] +; CHECK-NEXT: [[T1:%.*]] = icmp slt i64 [[T]], 0 +; CHECK-NEXT: [[T2:%.*]] = sub nsw i64 0, [[T]] +; CHECK-NEXT: [[T3:%.*]] = select i1 [[T1]], i64 [[T2]], i64 [[T]] +; CHECK-NEXT: ret i64 [[T3]] +; + %t = sub i64 ptrtoint (i64* @g to i64), %arg + %t1 = icmp slt i64 %t, 0 + %t2 = sub nsw i64 0, %t + %t3 = select i1 %t1, i64 %t2, i64 %t + ret i64 %t3 +} |
