Pass through constantexprs

Author: arsenm

llvm/lib/Analysis/ConstantFolding.cpp

@@ -1346,7 +1346,7 @@ Constant *llvm::FlushFPConstant(Constant *Operand, const Instruction *Inst,
   if (ConstantFP *CFP = dyn_cast<ConstantFP>(Operand))
     return flushDenormalConstantFP(CFP, Inst, IsOutput);
 
-  if (isa<ConstantAggregateZero, UndefValue>(Operand))
+  if (isa<ConstantAggregateZero, UndefValue, ConstantExpr>(Operand))
     return Operand;
 
   Type *Ty = Operand->getType();

llvm/test/Transforms/InstSimplify/ConstProp/bitcast.ll

@@ -66,17 +66,15 @@ define i1 @fcmp_constexpr_une(float %conv) {
 
 define i1 @fcmp_constexpr_ueq(float %conv) {
 ; CHECK-LABEL: @fcmp_constexpr_ueq(
-; CHECK-NEXT:    [[CMP:%.*]] = fcmp ueq float bitcast (i32 ptrtoint (ptr @a to i32) to float), bitcast (i32 ptrtoint (ptr @a to i32) to float)
-; CHECK-NEXT:    ret i1 [[CMP]]
+; CHECK-NEXT:    ret i1 true
 ;
   %cmp = fcmp ueq float bitcast (i32 ptrtoint (ptr @a to i32) to float), bitcast (i32 ptrtoint (ptr @a to i32) to float)
   ret i1 %cmp
 }
 
 define i1 @fcmp_constexpr_one(float %conv) {
 ; CHECK-LABEL: @fcmp_constexpr_one(
-; CHECK-NEXT:    [[CMP:%.*]] = fcmp one float bitcast (i32 ptrtoint (ptr @a to i32) to float), bitcast (i32 ptrtoint (ptr @a to i32) to float)
-; CHECK-NEXT:    ret i1 [[CMP]]
+; CHECK-NEXT:    ret i1 false
 ;
   %cmp = fcmp one float bitcast (i32 ptrtoint (ptr @a to i32) to float), bitcast (i32 ptrtoint (ptr @a to i32) to float)
   ret i1 %cmp