diff options
| -rw-r--r-- | llvm/lib/Transforms/Scalar/DivRemPairs.cpp | 2 | ||||
| -rw-r--r-- | llvm/test/Transforms/DivRemPairs/X86/div-expanded-rem-pair.ll | 36 |
2 files changed, 36 insertions, 2 deletions
diff --git a/llvm/lib/Transforms/Scalar/DivRemPairs.cpp b/llvm/lib/Transforms/Scalar/DivRemPairs.cpp index 4f53874c096..93485350747 100644 --- a/llvm/lib/Transforms/Scalar/DivRemPairs.cpp +++ b/llvm/lib/Transforms/Scalar/DivRemPairs.cpp @@ -233,8 +233,6 @@ static bool optimizeDivRem(Function &F, const TargetTransformInfo &TTI, if (!DivDominates && !DT.dominates(RemInst, DivInst)) { // We have matching div-rem pair, but they are in two different blocks, // neither of which dominates one another. - assert(!RemOriginallyWasInExpandedForm && - "Won't happen for expanded-form rem."); // FIXME: We could hoist both ops to the common predecessor block? continue; } diff --git a/llvm/test/Transforms/DivRemPairs/X86/div-expanded-rem-pair.ll b/llvm/test/Transforms/DivRemPairs/X86/div-expanded-rem-pair.ll index 792ef9c0ece..7c43d87ffa5 100644 --- a/llvm/test/Transforms/DivRemPairs/X86/div-expanded-rem-pair.ll +++ b/llvm/test/Transforms/DivRemPairs/X86/div-expanded-rem-pair.ll @@ -168,3 +168,39 @@ end: %ret = phi i128 [ %rem, %if ], [ 3, %entry ] ret i128 %ret } + +; Even in expanded form, we can end up with div and rem in different basic +; blocks neither of which dominates each another. +define i32 @can_have_divrem_in_mutually_nondominating_bbs(i1 %cmp, i32 %a, i32 %b) { +; CHECK-LABEL: @can_have_divrem_in_mutually_nondominating_bbs( +; CHECK-NEXT: entry: +; CHECK-NEXT: br i1 [[CMP:%.*]], label [[IF_THEN:%.*]], label [[IF_ELSE:%.*]] +; CHECK: if.then: +; CHECK-NEXT: [[T0:%.*]] = udiv i32 [[A:%.*]], [[B:%.*]] +; CHECK-NEXT: [[T1:%.*]] = mul nuw i32 [[T0]], [[B]] +; CHECK-NEXT: [[T2_RECOMPOSED:%.*]] = urem i32 [[A]], [[B]] +; CHECK-NEXT: br label [[END:%.*]] +; CHECK: if.else: +; CHECK-NEXT: [[T3:%.*]] = udiv i32 [[A]], [[B]] +; CHECK-NEXT: br label [[END]] +; CHECK: end: +; CHECK-NEXT: [[RET:%.*]] = phi i32 [ [[T2_RECOMPOSED]], [[IF_THEN]] ], [ [[T3]], [[IF_ELSE]] ] +; CHECK-NEXT: ret i32 [[RET]] +; +entry: + br i1 %cmp, label %if.then, label %if.else + +if.then: + %t0 = udiv i32 %a, %b + %t1 = mul nuw i32 %t0, %b + %t2 = sub i32 %a, %t1 + br label %end + +if.else: + %t3 = udiv i32 %a, %b + br label %end + +end: + %ret = phi i32 [ %t2, %if.then ], [ %t3, %if.else ] + ret i32 %ret +} |
