diff options
| -rw-r--r-- | llvm/test/Transforms/SimplifyCFG/unsigned-multiplication-will-overflow.ll | 38 |
1 files changed, 38 insertions, 0 deletions
diff --git a/llvm/test/Transforms/SimplifyCFG/unsigned-multiplication-will-overflow.ll b/llvm/test/Transforms/SimplifyCFG/unsigned-multiplication-will-overflow.ll new file mode 100644 index 00000000000..0c02fba2ec9 --- /dev/null +++ b/llvm/test/Transforms/SimplifyCFG/unsigned-multiplication-will-overflow.ll @@ -0,0 +1,38 @@ +; NOTE: Assertions have been autogenerated by utils/update_test_checks.py +; RUN: opt < %s -simplifycfg -S | FileCheck %s + +; This is checking that the multiplication does overflow, with a leftover +; guard against division-by-zero that was needed before InstCombine +; produced llvm.umul.with.overflow. + +define i1 @will_overflow(i64 %size, i64 %nmemb) { +; CHECK-LABEL: @will_overflow( +; CHECK-NEXT: entry: +; CHECK-NEXT: [[CMP:%.*]] = icmp eq i64 [[SIZE:%.*]], 0 +; CHECK-NEXT: br i1 [[CMP]], label [[LAND_END:%.*]], label [[LAND_RHS:%.*]] +; CHECK: land.rhs: +; CHECK-NEXT: [[UMUL:%.*]] = tail call { i64, i1 } @llvm.umul.with.overflow.i64(i64 [[SIZE]], i64 [[NMEMB:%.*]]) +; CHECK-NEXT: [[UMUL_OV:%.*]] = extractvalue { i64, i1 } [[UMUL]], 1 +; CHECK-NEXT: [[UMUL_NOT_OV:%.*]] = xor i1 [[UMUL_OV]], true +; CHECK-NEXT: br label [[LAND_END]] +; CHECK: land.end: +; CHECK-NEXT: [[TMP0:%.*]] = phi i1 [ true, [[ENTRY:%.*]] ], [ [[UMUL_NOT_OV]], [[LAND_RHS]] ] +; CHECK-NEXT: ret i1 [[TMP0]] +; +entry: + %cmp = icmp eq i64 %size, 0 + br i1 %cmp, label %land.end, label %land.rhs + +land.rhs: ; preds = %entry + %umul = tail call { i64, i1 } @llvm.umul.with.overflow.i64(i64 %size, i64 %nmemb) + %umul.ov = extractvalue { i64, i1 } %umul, 1 + %umul.not.ov = xor i1 %umul.ov, true + br label %land.end + +land.end: ; preds = %land.rhs, %entry + %0 = phi i1 [ true, %entry ], [ %umul.not.ov, %land.rhs ] + ret i1 %0 +} + +; Function Attrs: nounwind readnone speculatable +declare { i64, i1 } @llvm.umul.with.overflow.i64(i64, i64) #0 |
