[llvm] r369795 - Fix a bug in just submitted rL369789

[Philip Reames via llvm-commits]

Author: reames
Date: Fri Aug 23 11:27:57 2019
New Revision: 369795

URL: http://llvm.org/viewvc/llvm-project?rev=369795&view=rev
Log:
Fix a bug in just submitted rL369789

Started implementing the vector case and realized the scalar case hadn't handled the GEP producing a different type than the base correctly.  It's entertaining seeing what slips through review when we're focused on the 'hard' parts.  :(

Also adding an extra vector test as it happened to be in workspace and wasn't worth separating.


Modified:
    llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp
    llvm/trunk/test/Transforms/InstCombine/gep-inbounds-null.ll

Modified: llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp?rev=369795&r1=369794&r2=369795&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp (original)
+++ llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp Fri Aug 23 11:27:57 2019
@@ -914,7 +914,10 @@ Instruction *InstCombiner::foldGEPICmp(G
     // In general, we're allowed to make values less poison (i.e. remove
     //   sources of full UB), so in this case, we just select between the two
     //   non-poison cases (1 and 4 above).
-    return new ICmpInst(Cond, GEPLHS->getPointerOperand(), RHS);
+    auto *Base = GEPLHS->getPointerOperand();
+    return new ICmpInst(Cond, Base,
+                        ConstantExpr::getBitCast(cast<Constant>(RHS),
+                                                 Base->getType()));
   } else if (GEPOperator *GEPRHS = dyn_cast<GEPOperator>(RHS)) {
     // If the base pointers are different, but the indices are the same, just
     // compare the base pointer.

Modified: llvm/trunk/test/Transforms/InstCombine/gep-inbounds-null.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/gep-inbounds-null.ll?rev=369795&r1=369794&r2=369795&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/gep-inbounds-null.ll (original)
+++ llvm/trunk/test/Transforms/InstCombine/gep-inbounds-null.ll Fri Aug 23 11:27:57 2019
@@ -102,6 +102,19 @@ entry:
   ret <2 x i1> %cnd
 }
 
+define <2 x i1> @test_vector_both(<2 x i8*> %base, <2 x i64> %idx) {
+; CHECK-LABEL: @test_vector_both(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[GEP:%.*]] = getelementptr inbounds i8, <2 x i8*> [[BASE:%.*]], <2 x i64> [[IDX:%.*]]
+; CHECK-NEXT:    [[CND:%.*]] = icmp eq <2 x i8*> [[GEP]], zeroinitializer
+; CHECK-NEXT:    ret <2 x i1> [[CND]]
+;
+entry:
+  %gep = getelementptr inbounds i8, <2 x i8*> %base, <2 x i64> %idx
+  %cnd = icmp eq <2 x i8*> %gep, zeroinitializer
+  ret <2 x i1> %cnd
+}
+
 ;; These two show instsimplify's reasoning getting to the non-zero offsets
 ;; before instcombine does.
 
@@ -154,6 +167,19 @@ entry:
   ret i1 %cnd
 }
 
+
+define i1 @test_index_type([10 x i8]* %base, i64 %idx) {
+; CHECK-LABEL: @test_index_type(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[CND:%.*]] = icmp eq [10 x i8]* [[BASE:%.*]], null
+; CHECK-NEXT:    ret i1 [[CND]]
+;
+entry:
+  %gep = getelementptr inbounds [10 x i8], [10 x i8]* %base, i64 %idx, i64 %idx
+  %cnd = icmp eq i8* %gep, null
+  ret i1 %cnd
+}
+
 
 ;; Finally, some negative tests for sanity checking.