DenseMap<Value*,Value*> &SunkAddrs);
bool OptimizeInlineAsmInst(Instruction *I, CallSite CS,
DenseMap<Value*,Value*> &SunkAddrs);
+ bool MoveExtToFormExtLoad(Instruction *I);
bool OptimizeExtUses(Instruction *I);
void findLoopBackEdges(const Function &F);
};
return MadeChange;
}
+/// MoveExtToFormExtLoad - Move a zext or sext fed by a load into the same
+/// basic block as the load, unless conditions are unfavorable. This allows
+/// SelectionDAG to fold the extend into the load.
+///
+bool CodeGenPrepare::MoveExtToFormExtLoad(Instruction *I) {
+ // Look for a load being extended.
+ LoadInst *LI = dyn_cast<LoadInst>(I->getOperand(0));
+ if (!LI) return false;
+
+ // If they're already in the same block, there's nothing to do.
+ if (LI->getParent() == I->getParent())
+ return false;
+
+ // If the load has other users and the truncate is not free, this probably
+ // isn't worthwhile.
+ if (!LI->hasOneUse() &&
+ TLI && !TLI->isTruncateFree(I->getType(), LI->getType()))
+ return false;
+
+ // Check whether the target supports casts folded into loads.
+ unsigned LType;
+ if (isa<ZExtInst>(I))
+ LType = ISD::ZEXTLOAD;
+ else {
+ assert(isa<SExtInst>(I) && "Unexpected ext type!");
+ LType = ISD::SEXTLOAD;
+ }
+ if (TLI && !TLI->isLoadExtLegal(LType, TLI->getValueType(LI->getType())))
+ return false;
+
+ // Move the extend into the same block as the load, so that SelectionDAG
+ // can fold it.
+ I->removeFromParent();
+ I->insertAfter(LI);
+ return true;
+}
+
bool CodeGenPrepare::OptimizeExtUses(Instruction *I) {
BasicBlock *DefBB = I->getParent();
MadeChange |= Change;
}
- if (!Change && (isa<ZExtInst>(I) || isa<SExtInst>(I)))
+ if (!Change && (isa<ZExtInst>(I) || isa<SExtInst>(I))) {
+ MadeChange |= MoveExtToFormExtLoad(I);
MadeChange |= OptimizeExtUses(I);
+ }
} else if (CmpInst *CI = dyn_cast<CmpInst>(I)) {
MadeChange |= OptimizeCmpExpression(CI);
} else if (LoadInst *LI = dyn_cast<LoadInst>(I)) {
--- /dev/null
+; RUN: llc < %s -march=x86-64 | FileCheck %s
+; rdar://7304838
+
+; CodeGenPrepare should move the zext into the block with the load
+; so that SelectionDAG can select it with the load.
+
+; CHECK: movzbl (%rdi), %eax
+
+define void @foo(i8* %p, i32* %q) {
+entry:
+ %t = load i8* %p
+ %a = icmp slt i8 %t, 20
+ br i1 %a, label %true, label %false
+true:
+ %s = zext i8 %t to i32
+ store i32 %s, i32* %q
+ ret void
+false:
+ ret void
+}
; RUN: llc < %s -mtriple=x86_64-apple-darwin10 -relocation-model=pic -disable-fp-elim -color-ss-with-regs -stats -info-output-file - > %t
-; RUN: grep stackcoloring %t | grep "stack slot refs replaced with reg refs" | grep 5
-; RUN: grep asm-printer %t | grep 179
+; RUN: grep stackcoloring %t | grep "stack slot refs replaced with reg refs" | grep 6
+; RUN: grep asm-printer %t | grep 177
type { [62 x %struct.Bitvec*] } ; type %0
type { i8* } ; type %1