[llvm] r353467 - [InstCombine] Fix crashing from (icmp (bitcast ([su]itofp X)), Y)
Sanjay Patel via llvm-commits
llvm-commits at lists.llvm.org
Thu Feb 7 13:12:02 PST 2019
Author: spatel
Date: Thu Feb 7 13:12:01 2019
New Revision: 353467
URL: http://llvm.org/viewvc/llvm-project?rev=353467&view=rev
Log:
[InstCombine] Fix crashing from (icmp (bitcast ([su]itofp X)), Y)
This fixes a class of bugs introduced by D44367,
which transforms various cases of icmp (bitcast ([su]itofp X)), Y to icmp X, Y.
If the bitcast is between vector types with a different number of elements,
the current code will produce bad IR along the lines of: icmp <N x i32> ..., <M x i32> <...>.
This patch suppresses the transform if the bitcast changes the number of vector elements.
Patch by: @AndrewScheidecker (Andrew Scheidecker)
Differential Revision: https://reviews.llvm.org/D57871
Modified:
llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp
llvm/trunk/test/Transforms/InstCombine/cast-int-icmp-eq-0.ll
Modified: llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp?rev=353467&r1=353466&r2=353467&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp (original)
+++ llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp Thu Feb 7 13:12:01 2019
@@ -2510,38 +2510,42 @@ static Instruction *foldICmpBitCast(ICmp
if (!Bitcast)
return nullptr;
- // Zero-equality and sign-bit checks are preserved through sitofp + bitcast.
- // FIXME: This needs to check that the bitcast does not change the number of
- // elements in a vector.
ICmpInst::Predicate Pred = Cmp.getPredicate();
Value *Op1 = Cmp.getOperand(1);
Value *BCSrcOp = Bitcast->getOperand(0);
- Value *X;
- if (match(BCSrcOp, m_SIToFP(m_Value(X)))) {
- // icmp eq (bitcast (sitofp X)), 0 --> icmp eq X, 0
- // icmp ne (bitcast (sitofp X)), 0 --> icmp ne X, 0
- // icmp slt (bitcast (sitofp X)), 0 --> icmp slt X, 0
- // icmp sgt (bitcast (sitofp X)), 0 --> icmp sgt X, 0
- if ((Pred == ICmpInst::ICMP_EQ || Pred == ICmpInst::ICMP_SLT ||
- Pred == ICmpInst::ICMP_NE || Pred == ICmpInst::ICMP_SGT) &&
- match(Op1, m_Zero()))
- return new ICmpInst(Pred, X, ConstantInt::getNullValue(X->getType()));
-
- // icmp slt (bitcast (sitofp X)), 1 --> icmp slt X, 1
- if (Pred == ICmpInst::ICMP_SLT && match(Op1, m_One()))
- return new ICmpInst(Pred, X, ConstantInt::get(X->getType(), 1));
-
- // icmp sgt (bitcast (sitofp X)), -1 --> icmp sgt X, -1
- if (Pred == ICmpInst::ICMP_SGT && match(Op1, m_AllOnes()))
- return new ICmpInst(Pred, X, ConstantInt::getAllOnesValue(X->getType()));
- }
- // Zero-equality checks are preserved through unsigned floating-point casts:
- // icmp eq (bitcast (uitofp X)), 0 --> icmp eq X, 0
- // icmp ne (bitcast (uitofp X)), 0 --> icmp ne X, 0
- if (match(BCSrcOp, m_UIToFP(m_Value(X))))
- if (Cmp.isEquality() && match(Op1, m_Zero()))
- return new ICmpInst(Pred, X, ConstantInt::getNullValue(X->getType()));
+ // Make sure the bitcast doesn't change the number of vector elements.
+ if (Bitcast->getSrcTy()->getScalarSizeInBits() ==
+ Bitcast->getDestTy()->getScalarSizeInBits()) {
+ // Zero-equality and sign-bit checks are preserved through sitofp + bitcast.
+ Value *X;
+ if (match(BCSrcOp, m_SIToFP(m_Value(X)))) {
+ // icmp eq (bitcast (sitofp X)), 0 --> icmp eq X, 0
+ // icmp ne (bitcast (sitofp X)), 0 --> icmp ne X, 0
+ // icmp slt (bitcast (sitofp X)), 0 --> icmp slt X, 0
+ // icmp sgt (bitcast (sitofp X)), 0 --> icmp sgt X, 0
+ if ((Pred == ICmpInst::ICMP_EQ || Pred == ICmpInst::ICMP_SLT ||
+ Pred == ICmpInst::ICMP_NE || Pred == ICmpInst::ICMP_SGT) &&
+ match(Op1, m_Zero()))
+ return new ICmpInst(Pred, X, ConstantInt::getNullValue(X->getType()));
+
+ // icmp slt (bitcast (sitofp X)), 1 --> icmp slt X, 1
+ if (Pred == ICmpInst::ICMP_SLT && match(Op1, m_One()))
+ return new ICmpInst(Pred, X, ConstantInt::get(X->getType(), 1));
+
+ // icmp sgt (bitcast (sitofp X)), -1 --> icmp sgt X, -1
+ if (Pred == ICmpInst::ICMP_SGT && match(Op1, m_AllOnes()))
+ return new ICmpInst(Pred, X,
+ ConstantInt::getAllOnesValue(X->getType()));
+ }
+
+ // Zero-equality checks are preserved through unsigned floating-point casts:
+ // icmp eq (bitcast (uitofp X)), 0 --> icmp eq X, 0
+ // icmp ne (bitcast (uitofp X)), 0 --> icmp ne X, 0
+ if (match(BCSrcOp, m_UIToFP(m_Value(X))))
+ if (Cmp.isEquality() && match(Op1, m_Zero()))
+ return new ICmpInst(Pred, X, ConstantInt::getNullValue(X->getType()));
+ }
// Test to see if the operands of the icmp are casted versions of other
// values. If the ptr->ptr cast can be stripped off both arguments, do so.
Modified: llvm/trunk/test/Transforms/InstCombine/cast-int-icmp-eq-0.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/cast-int-icmp-eq-0.ll?rev=353467&r1=353466&r2=353467&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/cast-int-icmp-eq-0.ll (original)
+++ llvm/trunk/test/Transforms/InstCombine/cast-int-icmp-eq-0.ll Thu Feb 7 13:12:01 2019
@@ -651,3 +651,59 @@ define <3 x i1> @i16_cast_cmp_sgt_int_m1
ret <3 x i1> %cmp
}
+; Verify that the various forms of this transform are not applied when the
+; bitcast changes the number of vector elements:
+; icmp (bitcast ([su]itofp X)), Y -> icmp X, Y
+
+define <6 x i1> @i16_cast_cmp_sgt_int_m1_bitcast_vector_num_elements_sitofp(<3 x i16> %i) {
+; CHECK-LABEL: @i16_cast_cmp_sgt_int_m1_bitcast_vector_num_elements_sitofp(
+; CHECK-NEXT: [[F:%.*]] = sitofp <3 x i16> [[I:%.*]] to <3 x float>
+; CHECK-NEXT: [[B:%.*]] = bitcast <3 x float> [[F]] to <6 x i16>
+; CHECK-NEXT: [[CMP:%.*]] = icmp sgt <6 x i16> [[B]], <i16 -1, i16 -1, i16 -1, i16 -1, i16 -1, i16 -1>
+; CHECK-NEXT: ret <6 x i1> [[CMP]]
+;
+ %f = sitofp <3 x i16> %i to <3 x float>
+ %b = bitcast <3 x float> %f to <6 x i16>
+ %cmp = icmp sgt <6 x i16> %b, <i16 -1, i16 -1, i16 -1, i16 -1, i16 -1, i16 -1>
+ ret <6 x i1> %cmp
+}
+
+define i1 @i16_cast_cmp_sgt_int_m1_bitcast_vector_to_scalar_sitofp(<3 x i16> %i) {
+; CHECK-LABEL: @i16_cast_cmp_sgt_int_m1_bitcast_vector_to_scalar_sitofp(
+; CHECK-NEXT: [[F:%.*]] = sitofp <3 x i16> [[I:%.*]] to <3 x float>
+; CHECK-NEXT: [[B:%.*]] = bitcast <3 x float> [[F]] to i96
+; CHECK-NEXT: [[CMP:%.*]] = icmp sgt i96 [[B]], -1
+; CHECK-NEXT: ret i1 [[CMP]]
+;
+ %f = sitofp <3 x i16> %i to <3 x float>
+ %b = bitcast <3 x float> %f to i96
+ %cmp = icmp sgt i96 %b, -1
+ ret i1 %cmp
+}
+
+
+define <6 x i1> @i16_cast_cmp_eq_int_0_bitcast_vector_num_elements_uitofp(<3 x i16> %i) {
+; CHECK-LABEL: @i16_cast_cmp_eq_int_0_bitcast_vector_num_elements_uitofp(
+; CHECK-NEXT: [[F:%.*]] = uitofp <3 x i16> [[I:%.*]] to <3 x float>
+; CHECK-NEXT: [[B:%.*]] = bitcast <3 x float> [[F]] to <6 x i16>
+; CHECK-NEXT: [[CMP:%.*]] = icmp eq <6 x i16> [[B]], zeroinitializer
+; CHECK-NEXT: ret <6 x i1> [[CMP]]
+;
+ %f = uitofp <3 x i16> %i to <3 x float>
+ %b = bitcast <3 x float> %f to <6 x i16>
+ %cmp = icmp eq <6 x i16> %b, <i16 0, i16 0, i16 0, i16 0, i16 0, i16 0>
+ ret <6 x i1> %cmp
+}
+
+define i1 @i16_cast_cmp_eq_int_0_bitcast_vector_to_scalar_uitofp(<3 x i16> %i) {
+; CHECK-LABEL: @i16_cast_cmp_eq_int_0_bitcast_vector_to_scalar_uitofp(
+; CHECK-NEXT: [[F:%.*]] = uitofp <3 x i16> [[I:%.*]] to <3 x float>
+; CHECK-NEXT: [[B:%.*]] = bitcast <3 x float> [[F]] to i96
+; CHECK-NEXT: [[CMP:%.*]] = icmp eq i96 [[B]], 0
+; CHECK-NEXT: ret i1 [[CMP]]
+;
+ %f = uitofp <3 x i16> %i to <3 x float>
+ %b = bitcast <3 x float> %f to i96
+ %cmp = icmp eq i96 %b, 0
+ ret i1 %cmp
+}
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