[InstCombine] Make sure that LHS and RHS have the same type in

transformToIndexedCompare

If they don't have the same type, the size of the constant
index would need to be adjusted (and this wouldn't be always
possible).

Alternatively we could try the analysis with the initial
RHS value, which would guarantee that the two sides have
the same type. However it is unlikely that in practice this
would pass our transformation requirements.

Fixes PR31808 (https://llvm.org/bugs/show_bug.cgi?id=31808).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@293629 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Transforms/InstCombine/InstCombineCompares.cpp b/lib/Transforms/InstCombine/InstCombineCompares.cpp
index 3a1be81b7f58bf0cc8c7f57cc860ecfb741ae449..1ce776c7f9b2457e701c4a0b6dc429d0bcca5b7d 100644 (file)
--- a/lib/Transforms/InstCombine/InstCombineCompares.cpp
+++ b/lib/Transforms/InstCombine/InstCombineCompares.cpp
@@ -884,6 +884,10 @@ static Instruction *transformToIndexedCompare(GEPOperator *GEPLHS, Value *RHS,
   if (!GEPLHS->hasAllConstantIndices())
     return nullptr;
 
+  // Make sure the pointers have the same type.
+  if (GEPLHS->getType() != RHS->getType())
+    return nullptr;
+
   Value *PtrBase, *Index;
   std::tie(PtrBase, Index) = getAsConstantIndexedAddress(GEPLHS, DL);
 

diff --git a/test/Transforms/InstCombine/indexed-gep-compares.ll b/test/Transforms/InstCombine/indexed-gep-compares.ll
index 64dff271297630fc8bc47c50298ff253d42107b7..71afed438d10f6101c52c3a08accff394d16a55e 100644 (file)
--- a/test/Transforms/InstCombine/indexed-gep-compares.ll
+++ b/test/Transforms/InstCombine/indexed-gep-compares.ll
@@ -188,3 +188,20 @@ bb10:
 
 
 declare i32 @__gxx_personality_v0(...)
+
+define i1 @test8(i64* %in, i64 %offset) {
+entry:
+
+ %ld = load i64, i64* %in, align 8
+ %casti8 = inttoptr i64 %ld to i8*
+ %gepi8 = getelementptr inbounds i8, i8* %casti8, i64 %offset
+ %cast = bitcast i8* %gepi8 to i32**
+ %ptrcast = inttoptr i64 %ld to i32**
+ %gepi32 = getelementptr inbounds i32*, i32** %ptrcast, i64 1
+ %cmp = icmp eq i32** %gepi32, %cast
+ ret i1 %cmp
+
+
+; CHECK-LABEL: @test8(
+; CHECK-NOT: icmp eq i32 %{{[0-9A-Za-z.]+}}, 1
+}