[llvm] 4858e08 - [ConstraintElimination] Only strip casts preserving the representation.

[Florian Hahn via llvm-commits]

Author: Florian Hahn
Date: 2021-03-26T20:07:41Z
New Revision: 4858e081d764537309e8200f144402fb73d603e4

URL: https://github.com/llvm/llvm-project/commit/4858e081d764537309e8200f144402fb73d603e4
DIFF: https://github.com/llvm/llvm-project/commit/4858e081d764537309e8200f144402fb73d603e4.diff

LOG: [ConstraintElimination] Only strip casts preserving the representation.

Things like addrspacecast may not be no-ops, so we should not look
through them.

Added: 
    

Modified: 
    llvm/lib/Transforms/Scalar/ConstraintElimination.cpp
    llvm/test/Transforms/ConstraintElimination/pointercast.ll

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Transforms/Scalar/ConstraintElimination.cpp b/llvm/lib/Transforms/Scalar/ConstraintElimination.cpp
index f133f865945f8..16cde39ecff93 100644
--- a/llvm/lib/Transforms/Scalar/ConstraintElimination.cpp
+++ b/llvm/lib/Transforms/Scalar/ConstraintElimination.cpp
@@ -166,8 +166,8 @@ getConstraint(CmpInst::Predicate Pred, Value *Op0, Value *Op1,
   if (Pred != CmpInst::ICMP_ULE && Pred != CmpInst::ICMP_ULT)
     return {};
 
-  auto ADec = decompose(Op0->stripPointerCasts());
-  auto BDec = decompose(Op1->stripPointerCasts());
+  auto ADec = decompose(Op0->stripPointerCastsSameRepresentation());
+  auto BDec = decompose(Op1->stripPointerCastsSameRepresentation());
   // Skip if decomposing either of the values failed.
   if (ADec.empty() || BDec.empty())
     return {};

diff  --git a/llvm/test/Transforms/ConstraintElimination/pointercast.ll b/llvm/test/Transforms/ConstraintElimination/pointercast.ll
index 5811b69118caf..acd0fbcdcf9bb 100644
--- a/llvm/test/Transforms/ConstraintElimination/pointercast.ll
+++ b/llvm/test/Transforms/ConstraintElimination/pointercast.ll
@@ -174,19 +174,19 @@ define i1 @addrspacecast_and_cmp(i32* readonly %src, i32* readnone %min, i32* re
 ; CHECK:       checks:
 ; CHECK-NEXT:    [[C_3_MIN:%.*]] = icmp ult i32* [[GEP_3]], [[MIN]]
 ; CHECK-NEXT:    [[C_3_MAX:%.*]] = icmp ult i32* [[GEP_3]], [[MAX]]
-; CHECK-NEXT:    [[RES_1:%.*]] = xor i1 false, [[C_3_MAX]]
+; CHECK-NEXT:    [[RES_1:%.*]] = xor i1 [[C_3_MIN]], [[C_3_MAX]]
 ; CHECK-NEXT:    [[GEP_1:%.*]] = getelementptr inbounds i32, i32* [[SRC]], i64 1
 ; CHECK-NEXT:    [[C_1_MIN:%.*]] = icmp ult i32* [[GEP_1]], [[MIN]]
 ; CHECK-NEXT:    [[C_1_MAX:%.*]] = icmp ult i32* [[GEP_1]], [[MAX]]
-; CHECK-NEXT:    [[RES_2:%.*]] = xor i1 false, true
+; CHECK-NEXT:    [[RES_2:%.*]] = xor i1 [[C_1_MIN]], [[C_1_MAX]]
 ; CHECK-NEXT:    [[GEP_2:%.*]] = getelementptr inbounds i32, i32* [[SRC]], i64 2
 ; CHECK-NEXT:    [[C_2_MIN:%.*]] = icmp ult i32* [[GEP_2]], [[MIN]]
 ; CHECK-NEXT:    [[C_2_MAX:%.*]] = icmp ult i32* [[GEP_2]], [[MAX]]
-; CHECK-NEXT:    [[RES_3:%.*]] = xor i1 false, true
+; CHECK-NEXT:    [[RES_3:%.*]] = xor i1 [[C_2_MIN]], [[C_2_MAX]]
 ; CHECK-NEXT:    [[GEP_4:%.*]] = getelementptr inbounds i32, i32* [[SRC]], i64 4
 ; CHECK-NEXT:    [[C_4_MIN:%.*]] = icmp ult i32* [[GEP_4]], [[MIN]]
 ; CHECK-NEXT:    [[C_4_MAX:%.*]] = icmp ult i32* [[GEP_4]], [[MAX]]
-; CHECK-NEXT:    [[RES_4:%.*]] = xor i1 false, [[C_4_MAX]]
+; CHECK-NEXT:    [[RES_4:%.*]] = xor i1 [[C_4_MIN]], [[C_4_MAX]]
 ; CHECK-NEXT:    [[RES_5:%.*]] = xor i1 [[RES_1]], [[RES_2]]
 ; CHECK-NEXT:    [[RES_6:%.*]] = xor i1 [[RES_5]], [[RES_3]]
 ; CHECK-NEXT:    [[RES_7:%.*]] = xor i1 [[RES_6]], [[RES_4]]