To ensure that we have more accurate line information for a block

don't elide the branch instruction if it's the only one in the block,
otherwise it's ok.

PR9796 and rdar://11215207

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@154417 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Eric Christopher 2012-04-10 18:18:10 +00:00
parent b79855ee18
commit 18112d83e7
2 changed files with 7 additions and 3 deletions

View File

@ -821,8 +821,11 @@ FastISel::SelectInstruction(const Instruction *I) {
/// the CFG.
void
FastISel::FastEmitBranch(MachineBasicBlock *MSucc, DebugLoc DL) {
if (FuncInfo.MBB->isLayoutSuccessor(MSucc)) {
// The unconditional fall-through case, which needs no instructions.
if (FuncInfo.MBB->getBasicBlock()->size() > 1 && FuncInfo.MBB->isLayoutSuccessor(MSucc)) {
// For more accurate line information if this is the only instruction
// in the block then emit it, otherwise we have the unconditional
// fall-through case, which needs no instructions.
} else {
// The unconditional branch case.
TII.InsertBranch(*FuncInfo.MBB, MSucc, NULL,

View File

@ -5,7 +5,7 @@ define i32 @t1(i32 %a, i32 %b) nounwind uwtable ssp {
entry:
; THUMB: t1:
; ARM: t1:
%x = add i32 %a, %b
br i1 1, label %if.then, label %if.else
; THUMB-NOT: b LBB0_1
; ARM-NOT: b LBB0_1
@ -24,6 +24,7 @@ if.then2: ; preds = %if.else
br label %if.end6
if.else3: ; preds = %if.else
%y = sub i32 %a, %b
br i1 1, label %if.then5, label %if.end
; THUMB-NOT: b LBB0_5
; ARM-NOT: b LBB0_5