diff options
| -rw-r--r-- | lib/Transforms/Scalar/StructurizeCFG.cpp | 14 | ||||
| -rw-r--r-- | test/Transforms/StructurizeCFG/no-branch-to-entry.ll | 31 |
2 files changed, 45 insertions, 0 deletions
diff --git a/lib/Transforms/Scalar/StructurizeCFG.cpp b/lib/Transforms/Scalar/StructurizeCFG.cpp index 0124dfdbeb..5045ff8fdf 100644 --- a/lib/Transforms/Scalar/StructurizeCFG.cpp +++ b/lib/Transforms/Scalar/StructurizeCFG.cpp @@ -779,6 +779,20 @@ void StructurizeCFG::handleLoops(bool ExitUseAllowed, handleLoops(false, LoopEnd); } + // If the start of the loop is the entry block, we can't branch to it so + // insert a new dummy entry block. + Function *LoopFunc = LoopStart->getParent(); + if (LoopStart == &LoopFunc->getEntryBlock()) { + LoopStart->setName("entry.orig"); + + BasicBlock *NewEntry = + BasicBlock::Create(LoopStart->getContext(), + "entry", + LoopFunc, + LoopStart); + BranchInst::Create(LoopStart, NewEntry); + } + // Create an extra loop end node LoopEnd = needPrefix(false); BasicBlock *Next = needPostfix(LoopEnd, ExitUseAllowed); diff --git a/test/Transforms/StructurizeCFG/no-branch-to-entry.ll b/test/Transforms/StructurizeCFG/no-branch-to-entry.ll new file mode 100644 index 0000000000..2e22c87153 --- /dev/null +++ b/test/Transforms/StructurizeCFG/no-branch-to-entry.ll @@ -0,0 +1,31 @@ +; RUN: opt -S -o - -structurizecfg < %s | FileCheck %s + +; CHECK-LABEL: @no_branch_to_entry_undef( +; CHECK: entry: +; CHECK-NEXT: br label %entry.orig +define void @no_branch_to_entry_undef(i32 addrspace(1)* %out) { +entry: + br i1 undef, label %for.end, label %for.body + +for.body: ; preds = %entry, %for.body + store i32 999, i32 addrspace(1)* %out, align 4 + br label %for.body + +for.end: ; preds = %Flow + ret void +} + +; CHECK-LABEL: @no_branch_to_entry_true( +; CHECK: entry: +; CHECK-NEXT: br label %entry.orig +define void @no_branch_to_entry_true(i32 addrspace(1)* %out) { +entry: + br i1 true, label %for.end, label %for.body + +for.body: ; preds = %entry, %for.body + store i32 999, i32 addrspace(1)* %out, align 4 + br label %for.body + +for.end: ; preds = %Flow + ret void +} |