Move EmitBranchOnBoolExpr and ConstantFoldsToSimpleInteger to
CodeGenFunction.cpp. Change VisitConditionalOperator to use
constant fold instead of codegen'ing a constant conditional.
Change ForStmt to use EmitBranchOnBoolExpr, this shrinks
expr.c very slightly to 40239 lines.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@59113 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/CGStmt.cpp b/lib/CodeGen/CGStmt.cpp
index 551a4c0..88da20d 100644
--- a/lib/CodeGen/CGStmt.cpp
+++ b/lib/CodeGen/CGStmt.cpp
@@ -14,7 +14,6 @@
#include "CGDebugInfo.h"
#include "CodeGenModule.h"
#include "CodeGenFunction.h"
-#include "clang/AST/APValue.h"
#include "clang/AST/StmtVisitor.h"
#include "clang/Basic/TargetInfo.h"
#include "llvm/InlineAsm.h"
@@ -224,98 +223,13 @@
Builder.ClearInsertionPoint();
}
-
-/// 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.
-static int ConstantFoldsToSimpleInteger(const Expr *Cond, ASTContext &Ctx) {
- APValue V;
- if (!Cond->tryEvaluate(V, Ctx))
- return 0; // Not foldable.
-
- if (CodeGenFunction::ContainsLabel(Cond))
- return 0; // Contains a label.
-
- return V.getInt().getBoolValue() ? 1 : -1;
-}
-
-
-/// EmitBranchOnBoolExpr - Emit a branch on a boolean condition (e.g. for an if
-/// statement) to the specified blocks. Based on the condition, this might try
-/// to simplify the codegen of the conditional based on the branch.
-///
-void CodeGenFunction::EmitBranchOnBoolExpr(const Expr *Cond,
- llvm::BasicBlock *TrueBlock,
- llvm::BasicBlock *FalseBlock) {
- if (const ParenExpr *PE = dyn_cast<ParenExpr>(Cond))
- return EmitBranchOnBoolExpr(PE->getSubExpr(), TrueBlock, FalseBlock);
-
- if (const BinaryOperator *CondBOp = dyn_cast<BinaryOperator>(Cond)) {
- // Handle X && Y in a condition.
- if (CondBOp->getOpcode() == BinaryOperator::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(), getContext()) == 1) {
- // 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(), getContext()) == 1) {
- // br(X && 1) -> br(X).
- return EmitBranchOnBoolExpr(CondBOp->getLHS(), TrueBlock, FalseBlock);
- }
-
- // Emit the LHS as a conditional. If the LHS conditional is false, we
- // want to jump to the FalseBlock.
- llvm::BasicBlock *LHSTrue = createBasicBlock("land_lhs_true");
- EmitBranchOnBoolExpr(CondBOp->getLHS(), LHSTrue, FalseBlock);
- EmitBlock(LHSTrue);
-
- EmitBranchOnBoolExpr(CondBOp->getRHS(), TrueBlock, FalseBlock);
- return;
- } else if (CondBOp->getOpcode() == BinaryOperator::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(), getContext()) == -1) {
- // 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(), getContext()) == -1) {
- // br(X || 0) -> br(X).
- return EmitBranchOnBoolExpr(CondBOp->getLHS(), TrueBlock, FalseBlock);
- }
-
- // Emit the LHS as a conditional. If the LHS conditional is true, we
- // want to jump to the TrueBlock.
- llvm::BasicBlock *LHSFalse = createBasicBlock("lor_lhs_false");
- EmitBranchOnBoolExpr(CondBOp->getLHS(), TrueBlock, LHSFalse);
- EmitBlock(LHSFalse);
-
- EmitBranchOnBoolExpr(CondBOp->getRHS(), TrueBlock, FalseBlock);
- return;
- }
-
- }
-
- // Emit the code with the fully general case.
- llvm::Value *CondV = EvaluateExprAsBool(Cond);
- Builder.CreateCondBr(CondV, TrueBlock, FalseBlock);
-}
-
-
void CodeGenFunction::EmitIfStmt(const IfStmt &S) {
// C99 6.8.4.1: The first substatement is executed if the expression compares
// unequal to 0. The condition must be a scalar type.
// If the condition constant folds and can be elided, try to avoid emitting
// the condition and the dead arm of the if/else.
- if (int Cond = ConstantFoldsToSimpleInteger(S.getCond(), getContext())) {
+ if (int Cond = ConstantFoldsToSimpleInteger(S.getCond())) {
// Figure out which block (then or else) is executed.
const Stmt *Executed = S.getThen(), *Skipped = S.getElse();
if (Cond == -1) // Condition false?
@@ -382,7 +296,7 @@
// As long as the condition is true, go to the loop body.
if (EmitBoolCondBranch)
Builder.CreateCondBr(BoolCondVal, LoopBody, ExitBlock);
-
+
// Store the blocks to use for break and continue.
BreakContinueStack.push_back(BreakContinue(ExitBlock, LoopHeader));
@@ -476,13 +390,13 @@
// Evaluate the condition if present. If not, treat it as a non-zero-constant
// according to 6.8.5.3p2, aka, true.
if (S.getCond()) {
- // C99 6.8.5p2/p4: The first substatement is executed if the expression
- // compares unequal to 0. The condition must be a scalar type.
- llvm::Value *BoolCondVal = EvaluateExprAsBool(S.getCond());
-
// As long as the condition is true, iterate the loop.
llvm::BasicBlock *ForBody = createBasicBlock("forbody");
- Builder.CreateCondBr(BoolCondVal, ForBody, AfterFor);
+
+ // C99 6.8.5p2/p4: The first substatement is executed if the expression
+ // compares unequal to 0. The condition must be a scalar type.
+ EmitBranchOnBoolExpr(S.getCond(), ForBody, AfterFor);
+
EmitBlock(ForBody);
} else {
// Treat it as a non-zero constant. Don't even create a new block for the