[llvm] r354380 - [ConstantFold] Fix misfolding of icmp with a bitcast FP second operand.
Andrew Scheidecker via llvm-commits
llvm-commits at lists.llvm.org
Tue Feb 19 13:03:20 PST 2019
Author: andrewscheidecker
Date: Tue Feb 19 13:03:20 2019
New Revision: 354380
URL: http://llvm.org/viewvc/llvm-project?rev=354380&view=rev
Log:
[ConstantFold] Fix misfolding of icmp with a bitcast FP second operand.
In the process of trying to eliminate the bitcast, this was producing a
malformed icmp with FP operands.
Differential revision: https://reviews.llvm.org/D51215
Modified:
llvm/trunk/lib/IR/ConstantFold.cpp
llvm/trunk/test/Transforms/ConstProp/bitcast.ll
Modified: llvm/trunk/lib/IR/ConstantFold.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/IR/ConstantFold.cpp?rev=354380&r1=354379&r2=354380&view=diff
==============================================================================
--- llvm/trunk/lib/IR/ConstantFold.cpp (original)
+++ llvm/trunk/lib/IR/ConstantFold.cpp Tue Feb 19 13:03:20 2019
@@ -1980,11 +1980,13 @@ Constant *llvm::ConstantFoldCompareInstr
// If the right hand side is a bitcast, try using its inverse to simplify
// it by moving it to the left hand side. We can't do this if it would turn
- // a vector compare into a scalar compare or visa versa.
+ // a vector compare into a scalar compare or visa versa, or if it would turn
+ // the operands into FP values.
if (ConstantExpr *CE2 = dyn_cast<ConstantExpr>(C2)) {
Constant *CE2Op0 = CE2->getOperand(0);
if (CE2->getOpcode() == Instruction::BitCast &&
- CE2->getType()->isVectorTy() == CE2Op0->getType()->isVectorTy()) {
+ CE2->getType()->isVectorTy() == CE2Op0->getType()->isVectorTy() &&
+ !CE2Op0->getType()->isFPOrFPVectorTy()) {
Constant *Inverse = ConstantExpr::getBitCast(C1, CE2Op0->getType());
return ConstantExpr::getICmp(pred, Inverse, CE2Op0);
}
Modified: llvm/trunk/test/Transforms/ConstProp/bitcast.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/ConstProp/bitcast.ll?rev=354380&r1=354379&r2=354380&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/ConstProp/bitcast.ll (original)
+++ llvm/trunk/test/Transforms/ConstProp/bitcast.ll Tue Feb 19 13:03:20 2019
@@ -10,19 +10,32 @@ define <1 x i64> @test1() {
ret <1 x i64> %A
}
-; FIXME: Don't try to propagate an FP source operand to an icmp.
+; Ensure that a FP source operand isn't propagated to an icmp.
@a = external global i16, align 1
@b = external global i16, align 1
define i1 @bad_icmp_constexpr_bitcast() {
; CHECK-LABEL: @bad_icmp_constexpr_bitcast(
-; CHECK-NEXT: ret i1 icmp eq (float bitcast (i32 ptrtoint (i16* @a to i32) to float), float fadd (float bitcast (i32 ptrtoint (i16* @b to i32) to float), float 2.000000e+00))
+; CHECK-NEXT: ret i1 icmp eq (i32 ptrtoint (i16* @a to i32), i32 bitcast (float fadd (float bitcast (i32 ptrtoint (i16* @b to i32) to float), float 2.000000e+00) to i32))
;
%cmp = icmp eq i32 ptrtoint (i16* @a to i32), bitcast (float fadd (float bitcast (i32 ptrtoint (i16* @b to i32) to float), float 2.0) to i32)
ret i1 %cmp
}
+; Ensure that an integer source operand isn't propagated to a fcmp.
+
+ at c = external global i16, align 1
+ at d = external global i16, align 1
+
+define i1 @bad_fcmp_constexpr_bitcast() {
+; CHECK-LABEL: @bad_fcmp_constexpr_bitcast(
+; CHECK-NEXT: ret i1 fcmp oeq (float bitcast (i32 ptrtoint (i16* @c to i32) to float), float bitcast (i32 add (i32 ptrtoint (i16* @d to i32), i32 2) to float))
+;
+ %cmp = fcmp oeq float bitcast (i32 ptrtoint (i16* @c to i32) to float), bitcast (i32 add (i32 ptrtoint (i16* @d to i32), i32 2) to float)
+ ret i1 %cmp
+}
+
; FIXME: If the bitcasts result in a NaN FP value, then "ordered and equal" would be false.
define i1 @fcmp_constexpr_oeq(float %conv) {
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