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While folding unconditional return move DbgRegionEndInst into the predecessor, instead of removing it. This fixes following tests from llvmgcc42 testsuite.

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gcc.c-torture/execute/20000605-3.c
gcc.c-torture/execute/20020619-1.c
gcc.c-torture/execute/20030920-1.c
gcc.c-torture/execute/loop-ivopts-1.c



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@65353 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Devang Patel 2009-02-24 00:05:16 +00:00
parent 53cac18cca
commit 5622f07a21
3 changed files with 14 additions and 25 deletions
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24
lib/Transforms/Utils/BasicBlockUtils.cpp
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@ -15,7 +15,6 @@
#include "llvm/Transforms/Utils/BasicBlockUtils.h"
#include "llvm/Function.h"
#include "llvm/Instructions.h"
#include "llvm/IntrinsicInst.h"
#include "llvm/Constant.h"
#include "llvm/Type.h"
#include "llvm/Analysis/AliasAnalysis.h"
@ -32,7 +31,7 @@ void llvm::DeleteDeadBlock(BasicBlock *BB) {
// Can delete self loop.
BB->getSinglePredecessor() == BB) && "Block is not dead!");
TerminatorInst *BBTerm = BB->getTerminator();
Value *DbgRegionEndContext = NULL;
// Loop through all of our successors and make sure they know that one
// of their predecessors is going away.
for (unsigned i = 0, e = BBTerm->getNumSuccessors(); i != e; ++i)
@ -41,10 +40,6 @@ void llvm::DeleteDeadBlock(BasicBlock *BB) {
// Zap all the instructions in the block.
while (!BB->empty()) {
Instruction &I = BB->back();
// It is possible to have multiple llvm.dbg.region.end in a block.
if (DbgRegionEndInst *DREI = dyn_cast<DbgRegionEndInst>(&I))
DbgRegionEndContext = DREI->getContext();
// If this instruction is used, replace uses with an arbitrary value.
// Because control flow can't get here, we don't care what we replace the
// value with. Note that since this block is unreachable, and all values
@ -54,22 +49,7 @@ void llvm::DeleteDeadBlock(BasicBlock *BB) {
I.replaceAllUsesWith(UndefValue::get(I.getType()));
BB->getInstList().pop_back();
}
if (DbgRegionEndContext) {
// Delete corresponding llvm.dbg.func.start from entry block.
BasicBlock &Entry = BB->getParent()->getEntryBlock();
DbgFuncStartInst *DbgFuncStart = NULL;
for (BasicBlock::iterator BI = Entry.begin(), BE = Entry.end();
BI != BE; ++BI) {
if (DbgFuncStartInst *DFSI = dyn_cast<DbgFuncStartInst>(BI)) {
DbgFuncStart = DFSI;
break;
}
}
if (DbgFuncStart && DbgFuncStart->getSubprogram() == DbgRegionEndContext)
DbgFuncStart->eraseFromParent();
}
// Zap the block!
BB->eraseFromParent();
}

9
lib/Transforms/Utils/SimplifyCFG.cpp
View File

@ -1789,6 +1789,13 @@ bool llvm::SimplifyCFG(BasicBlock *BB) {
Instruction *NewRet = RI->clone();
Pred->getInstList().push_back(NewRet);
BasicBlock::iterator BBI = RI;
if (BBI != BB->begin()) {
// Move region end info into the predecessor.
if (DbgRegionEndInst *DREI = dyn_cast<DbgRegionEndInst>(--BBI))
DREI->moveBefore(NewRet);
}
// If the return instruction returns a value, and if the value was a
// PHI node in "BB", propagate the right value into the return.
for (User::op_iterator i = NewRet->op_begin(), e = NewRet->op_end();
@ -1806,7 +1813,7 @@ bool llvm::SimplifyCFG(BasicBlock *BB) {
// If we eliminated all predecessors of the block, delete the block now.
if (pred_begin(BB) == pred_end(BB))
// We know there are no successors, so just nuke the block.
DeleteDeadBlock(BB);
M->getBasicBlockList().erase(BB);
return true;
}

6
test/Transforms/SimplifyCFG/dbginfo.ll
View File

@ -1,5 +1,7 @@
; RUN: llvm-as < %s | opt -simplifycfg | llvm-dis | grep region | count 1
; RUN: llvm-as < %s | opt -simplifycfg | llvm-dis | grep func.start | count 1
; RUN: llvm-as < %s | opt -simplifycfg | llvm-dis | grep region | count 2
; RUN: llvm-as < %s | opt -simplifycfg | llvm-dis | grep func.start | count 2
; RUN: llvm-as < %s | opt -simplifycfg | llvm-dis | not grep "br label"
%llvm.dbg.anchor.type = type { i32, i32 }
%llvm.dbg.basictype.type = type { i32, { }*, i8*, { }*, i32, i64, i64, i64, i32, i32 }
%llvm.dbg.compile_unit.type = type { i32, { }*, i32, i8*, i8*, i8*, i1, i1, i8* }