Value *OrigV = PN->getIncomingValueForBlock(BB);
Value *ThenV = PN->getIncomingValueForBlock(ThenBB);
+ // FIXME: Try to remove some of the duplication with HoistThenElseCodeToIf.
// Skip PHIs which are trivial.
if (ThenV == OrigV)
continue;
HaveRewritablePHIs = true;
- ConstantExpr *CE = dyn_cast<ConstantExpr>(ThenV);
- if (!CE)
+ ConstantExpr *OrigCE = dyn_cast<ConstantExpr>(OrigV);
+ ConstantExpr *ThenCE = dyn_cast<ConstantExpr>(ThenV);
+ if (!OrigCE && !ThenCE)
continue; // Known safe and cheap.
- if (!isSafeToSpeculativelyExecute(CE))
+ if ((ThenCE && !isSafeToSpeculativelyExecute(ThenCE)) ||
+ (OrigCE && !isSafeToSpeculativelyExecute(OrigCE)))
return false;
- if (ComputeSpeculationCost(CE) > PHINodeFoldingThreshold)
+ unsigned OrigCost = OrigCE ? ComputeSpeculationCost(OrigCE) : 0;
+ unsigned ThenCost = ThenCE ? ComputeSpeculationCost(ThenCE) : 0;
+ if (OrigCost + ThenCost > 2 * PHINodeFoldingThreshold)
return false;
// Account for the cost of an unfolded ConstantExpr which could end up
; RUN: opt < %s -simplifycfg -S | FileCheck %s
-; CHECK-NOT: select
@b = extern_weak global i32
+
define i32 @foo(i1 %y) {
+; CHECK: define i32 @foo(i1 %y) {
br i1 %y, label %bb1, label %bb2
bb1:
br label %bb3
br label %bb3
bb3:
%cond.i = phi i32 [ 0, %bb1 ], [ srem (i32 1, i32 zext (i1 icmp eq (i32* @b, i32* null) to i32)), %bb2 ]
+; CHECK: phi i32 {{.*}} srem (i32 1, i32 zext (i1 icmp eq (i32* @b, i32* null) to i32)), %bb2
ret i32 %cond.i
}
+
+define i32 @foo2(i1 %x) {
+; CHECK: define i32 @foo2(i1 %x) {
+bb0:
+ br i1 %x, label %bb1, label %bb2
+bb1:
+ br label %bb2
+bb2:
+ %cond = phi i32 [ 0, %bb1 ], [ srem (i32 1, i32 zext (i1 icmp eq (i32* @b, i32* null) to i32)), %bb0 ]
+; CHECK: %cond = phi i32 [ 0, %bb1 ], [ srem (i32 1, i32 zext (i1 icmp eq (i32* @b, i32* null) to i32)), %bb0 ]
+ ret i32 %cond
+}