Ignore dbg intrinsics while propagating conditional expression info.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@63876 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Devang Patel 2009-02-05 19:15:39 +00:00
parent ca940bb630
commit 1851db6b0f
5 changed files with 72 additions and 16 deletions

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@ -39,6 +39,14 @@ template<typename T> class SmallVectorImpl;
///
bool ConstantFoldTerminator(BasicBlock *BB);
//===----------------------------------------------------------------------===//
// CFG Simplification
//
/// isTerminatorFirstRelevantInsn - Return true if Term is very first
/// instruction ignoring Phi nodes and dbg intrinsics.
bool isTerminatorFirstRelevantInsn(BasicBlock *BB, Instruction *Term);
//===----------------------------------------------------------------------===//
// Local dead code elimination.
//

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@ -137,7 +137,7 @@ void CondProp::SimplifyPredecessors(BranchInst *BI) {
if (!PN->hasOneUse()) return;
BasicBlock *BB = BI->getParent();
if (&*BB->begin() != PN || &*next(BB->begin()) != BI)
if (!isTerminatorFirstRelevantInsn (BB, BI))
return;
// Ok, we have this really simple case, walk the PHI operands, looking for
@ -171,7 +171,7 @@ void CondProp::SimplifyPredecessors(SwitchInst *SI) {
if (!PN->hasOneUse()) return;
BasicBlock *BB = SI->getParent();
if (&*BB->begin() != PN || &*next(BB->begin()) != SI)
if (!isTerminatorFirstRelevantInsn (BB, SI))
return;
bool RemovedPreds = false;

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@ -148,6 +148,23 @@ bool llvm::ConstantFoldTerminator(BasicBlock *BB) {
return false;
}
//===----------------------------------------------------------------------===//
// CFG Simplification
//
/// isTerminatorFirstRelevantInsn - Return true if Term is very first
/// instruction ignoring Phi nodes and dbg intrinsics.
bool llvm::isTerminatorFirstRelevantInsn(BasicBlock *BB, Instruction *Term) {
BasicBlock::iterator BBI = Term;
while (BBI != BB->begin()) {
--BBI;
if (!isa<DbgInfoIntrinsic>(BBI))
break;
}
if (isa<PHINode>(BBI) || &*BBI == Term)
return true;
return false;
}
//===----------------------------------------------------------------------===//
// Local dead code elimination...

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@ -1330,20 +1330,6 @@ static bool FoldTwoEntryPHINode(PHINode *PN) {
return true;
}
/// isTerminatorFirstRelevantInsn - Return true if Term is very first
/// instruction ignoring Phi nodes and dbg intrinsics.
static bool isTerminatorFirstRelevantInsn(BasicBlock *BB, Instruction *Term) {
BasicBlock::iterator BBI = Term;
while (BBI != BB->begin()) {
--BBI;
if (!isa<DbgInfoIntrinsic>(BBI))
break;
}
if (isa<PHINode>(BBI) || &*BBI == Term)
return true;
return false;
}
/// SimplifyCondBranchToTwoReturns - If we found a conditional branch that goes
/// to two returning blocks, try to merge them together into one return,
/// introducing a select if the return values disagree.

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@ -0,0 +1,45 @@
; RUN: llvm-as < %s | opt -condprop | llvm-dis | \
; RUN: not grep {br label}
%llvm.dbg.anchor.type = type { i32, i32 }
%llvm.dbg.compile_unit.type = type { i32, { }*, i32, i8*, i8*, i8*, i1, i1, i8* }
@llvm.dbg.compile_units = linkonce constant %llvm.dbg.anchor.type { i32 458752, i32 17 }, section "llvm.metadata" ;
@.str = internal constant [4 x i8] c"a.c\00", section "llvm.metadata" ; <[4 x i8]*> [#uses=1]
@.str1 = internal constant [6 x i8] c"/tmp/\00", section "llvm.metadata" ; <[6 x i8]*> [#uses=1]
@.str2 = internal constant [55 x i8] c"4.2.1 (Based on Apple Inc. build 5636) (LLVM build 00)\00", section "llvm.metadata" ; <[55 x i8]*> [#uses=1]
@llvm.dbg.compile_unit = internal constant %llvm.dbg.compile_unit.type { i32 458769, { }* bitcast (%llvm.dbg.anchor.type* @llvm.dbg.compile_units to { }*), i32 1, i8* getelementptr ([4 x i8]* @.str, i32 0, i32 0), i8* getelementptr ([6 x i8]* @.str1, i32 0, i32 0), i8* getelementptr ([55 x i8]* @.str2, i32 0, i32 0), i1 true, i1 false, i8* null }, section "llvm.metadata" ; <%llvm.dbg.compile_unit.type*> [#uses=1]
declare void @llvm.dbg.stoppoint(i32, i32, { }*) nounwind
define i32 @test(i1 %C) {
br i1 %C, label %T1, label %F1
T1: ; preds = %0
call void @llvm.dbg.stoppoint(i32 5, i32 0, { }* bitcast (%llvm.dbg.compile_unit.type* @llvm.dbg.compile_unit to { }*))
br label %Cont
F1: ; preds = %0
call void @llvm.dbg.stoppoint(i32 5, i32 0, { }* bitcast (%llvm.dbg.compile_unit.type* @llvm.dbg.compile_unit to { }*))
br label %Cont
Cont: ; preds = %F1, %T1
%C2 = phi i1 [ false, %F1 ], [ true, %T1 ] ; <i1> [#uses=1]
call void @llvm.dbg.stoppoint(i32 5, i32 0, { }* bitcast (%llvm.dbg.compile_unit.type* @llvm.dbg.compile_unit to { }*))
br i1 %C2, label %T2, label %F2
T2: ; preds = %Cont
call void @llvm.dbg.stoppoint(i32 5, i32 0, { }* bitcast (%llvm.dbg.compile_unit.type* @llvm.dbg.compile_unit to { }*))
call void @bar( )
call void @llvm.dbg.stoppoint(i32 5, i32 0, { }* bitcast (%llvm.dbg.compile_unit.type* @llvm.dbg.compile_unit to { }*))
ret i32 17
F2: ; preds = %Cont
call void @llvm.dbg.stoppoint(i32 5, i32 0, { }* bitcast (%llvm.dbg.compile_unit.type* @llvm.dbg.compile_unit to { }*))
ret i32 1
}
declare void @bar()