nicolas/llvm-project
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Change the interface to ConstantFoldsToSimpleInteger to not encode

Browse Source 
a bool + success into one tri-state integer, simplifying things.

llvm-svn: 126592
This commit is contained in:
Chris Lattner
2011-02-27 23:02:32 +00:00
parent 2ca62f910d
commit 41c6ab538a
5 changed files with 42 additions and 29 deletions
Download Patch File Download Diff File Expand all files Collapse all files

35
clang/lib/CodeGen/CodeGenFunction.cpp
View File

@@ -408,22 +408,23 @@ bool CodeGenFunction::ContainsLabel(const Stmt *S, bool IgnoreCaseStmts) {
}
/// ConstantFoldsToSimpleInteger - If the sepcified expression does not fold to
/// a constant, or if it does but contains a label, return 0. If it constant
/// folds to 'true' and does not contain a label, return 1, if it constant folds
/// to 'false' and does not contain a label, return -1.
int CodeGenFunction::ConstantFoldsToSimpleInteger(const Expr *Cond) {
/// ConstantFoldsToSimpleInteger - If the specified expression does not fold
/// to a constant, or if it does but contains a label, return false. If it
/// constant folds return true and set the boolean result in Result.
bool CodeGenFunction::ConstantFoldsToSimpleInteger(const Expr *Cond,
bool &ResultBool) {
// FIXME: Rename and handle conversion of other evaluatable things
// to bool.
Expr::EvalResult Result;
if (!Cond->Evaluate(Result, getContext()) || !Result.Val.isInt() ||
Result.HasSideEffects)
return 0; // Not foldable, not integer or not fully evaluatable.
return false; // Not foldable, not integer or not fully evaluatable.
if (CodeGenFunction::ContainsLabel(Cond))
return 0; // Contains a label.
return false; // Contains a label.
return Result.Val.getInt().getBoolValue() ? 1 : -1;
ResultBool = Result.Val.getInt().getBoolValue();
return true;
}
@@ -442,14 +443,17 @@ void CodeGenFunction::EmitBranchOnBoolExpr(const Expr *Cond,
if (CondBOp->getOpcode() == BO_LAnd) {
// If we have "1 && X", simplify the code. "0 && X" would have constant
// folded if the case was simple enough.
if (ConstantFoldsToSimpleInteger(CondBOp->getLHS()) == 1) {
bool ConstantBool;
if (ConstantFoldsToSimpleInteger(CondBOp->getLHS(), ConstantBool) &&
ConstantBool) {
// br(1 && X) -> br(X).
return EmitBranchOnBoolExpr(CondBOp->getRHS(), TrueBlock, FalseBlock);
}
// If we have "X && 1", simplify the code to use an uncond branch.
// "X && 0" would have been constant folded to 0.
if (ConstantFoldsToSimpleInteger(CondBOp->getRHS()) == 1) {
if (ConstantFoldsToSimpleInteger(CondBOp->getRHS(), ConstantBool) &&
ConstantBool) {
// br(X && 1) -> br(X).
return EmitBranchOnBoolExpr(CondBOp->getLHS(), TrueBlock, FalseBlock);
}
@@ -468,17 +472,22 @@ void CodeGenFunction::EmitBranchOnBoolExpr(const Expr *Cond,
eval.end(*this);
return;
} else if (CondBOp->getOpcode() == BO_LOr) {
}
if (CondBOp->getOpcode() == BO_LOr) {
// If we have "0 || X", simplify the code. "1 || X" would have constant
// folded if the case was simple enough.
if (ConstantFoldsToSimpleInteger(CondBOp->getLHS()) == -1) {
bool ConstantBool;
if (ConstantFoldsToSimpleInteger(CondBOp->getLHS(), ConstantBool) &&
!ConstantBool) {
// br(0 || X) -> br(X).
return EmitBranchOnBoolExpr(CondBOp->getRHS(), TrueBlock, FalseBlock);
}
// If we have "X || 0", simplify the code to use an uncond branch.
// "X || 1" would have been constant folded to 1.
if (ConstantFoldsToSimpleInteger(CondBOp->getRHS()) == -1) {
if (ConstantFoldsToSimpleInteger(CondBOp->getRHS(), ConstantBool) &&
!ConstantBool) {
// br(X || 0) -> br(X).
return EmitBranchOnBoolExpr(CondBOp->getLHS(), TrueBlock, FalseBlock);
}