Revert "InstCombine: Clean up weird code that talks about a modulus that's long gone."

This causes crashes during the build of compiler-rt during selfhost. Add a
testcase for coverage.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@173279 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Transforms/InstCombine/InstructionCombining.cpp b/lib/Transforms/InstCombine/InstructionCombining.cpp
index e9e05ceb658ee8f1943393a488343c772f1dc89e..dc7fe5cf6b5bfe68324b923dcb6fee8c3e3ee8b8 100644 (file)
--- a/lib/Transforms/InstCombine/InstructionCombining.cpp
+++ b/lib/Transforms/InstCombine/InstructionCombining.cpp
@@ -758,7 +758,12 @@ Type *InstCombiner::FindElementAtOffset(Type *Ty, int64_t Offset,
     FirstIdx = Offset/TySize;
     Offset -= FirstIdx*TySize;
 
-    assert(Offset >= 0 && "Offset should never be negative!");
+    // Handle hosts where % returns negative instead of values [0..TySize).
+    if (Offset < 0) {
+      --FirstIdx;
+      Offset += TySize;
+      assert(Offset >= 0);
+    }
     assert((uint64_t)Offset < (uint64_t)TySize && "Out of range offset");
   }
 

diff --git a/test/Transforms/InstCombine/getelementptr.ll b/test/Transforms/InstCombine/getelementptr.ll
index 1c120ecbe9eb7361b1b86845a91b00158abc48f3..03e26eb67e9b114c739ad85be1b7c409a00d001c 100644 (file)
--- a/test/Transforms/InstCombine/getelementptr.ll
+++ b/test/Transforms/InstCombine/getelementptr.ll
@@ -492,3 +492,19 @@ define void @three_gep_f(%three_gep_t2* %x) {
 
 declare void @three_gep_g(i32*)
 declare void @three_gep_h(%three_gep_t2*)
+
+%struct.ham = type { i32, %struct.zot*, %struct.zot*, %struct.zot* }
+%struct.zot = type { i64, i8 }
+
+define void @test39(%struct.ham* %arg, i8 %arg1) nounwind {
+  %tmp = getelementptr inbounds %struct.ham* %arg, i64 0, i32 2
+  %tmp2 = load %struct.zot** %tmp, align 8
+  %tmp3 = bitcast %struct.zot* %tmp2 to i8*
+  %tmp4 = getelementptr inbounds i8* %tmp3, i64 -8
+  store i8 %arg1, i8* %tmp4, align 8
+  ret void
+
+; CHECK: @test39
+; CHECK: getelementptr inbounds %struct.ham* %arg, i64 0, i32 2
+; CHECK: getelementptr inbounds i8* %tmp3, i64 -8
+}