Merging r229029, minus the test which didn't work on the branch:

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r229029 | chandlerc | 2015-02-12 18:30:01 -0800 (Thu, 12 Feb 2015) | 16 lines

[IC] Fix a bug with the instcombine canonicalizing of loads and
propagating of metadata.

We were propagating !nonnull metadata even when the newly formed load is
no longer of a pointer type. This is clearly broken and results in LLVM
failing the verifier and aborting. This patch just restricts the
propagation of !nonnull metadata to when we actually have a pointer
type.

This bug report and the initial version of this patch was provided by
Charles Davis! Many thanks for finding this!

We still need to add logic to round-trip the metadata correctly if we
combine from pointer types to integer types and then back by using range
metadata for the integer type loads. But this is the minimal and safe
version of the patch, which is important so we can backport it into 3.6.
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/branches/release_36@229036 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp b/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp
index af1694d3453c4089e8e30591b8449017e0dc2681..6230c000cf57fb5273f19b2a8dafbcfca32b5c8e 100644 (file)
--- a/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp
+++ b/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp
@@ -330,11 +330,17 @@ static LoadInst *combineLoadToNewType(InstCombiner &IC, LoadInst &LI, Type *NewT
     case LLVMContext::MD_noalias:
     case LLVMContext::MD_nontemporal:
     case LLVMContext::MD_mem_parallel_loop_access:
-    case LLVMContext::MD_nonnull:
       // All of these directly apply.
       NewLoad->setMetadata(ID, N);
       break;
 
+    case LLVMContext::MD_nonnull:
+      // FIXME: We should translate this into range metadata for integer types
+      // and vice versa.
+      if (NewTy->isPointerTy())
+        NewLoad->setMetadata(ID, N);
+      break;
+
     case LLVMContext::MD_range:
       // FIXME: It would be nice to propagate this in some way, but the type
       // conversions make it hard.
@@ -548,13 +554,14 @@ static bool combineStoreToValueType(InstCombiner &IC, StoreInst &SI) {
       case LLVMContext::MD_noalias:
       case LLVMContext::MD_nontemporal:
       case LLVMContext::MD_mem_parallel_loop_access:
-      case LLVMContext::MD_nonnull:
         // All of these directly apply.
         NewStore->setMetadata(ID, N);
         break;
 
       case LLVMContext::MD_invariant_load:
+      case LLVMContext::MD_nonnull:
       case LLVMContext::MD_range:
+        // These don't apply for stores.
         break;
       }
     }

diff --git a/test/Transforms/InstCombine/loadstore-metadata.ll b/test/Transforms/InstCombine/loadstore-metadata.ll
index ad6a11cf6eb11bcb19cd338347b5da3b8a9a103a..3d18ac0e3344443c2653a11faf18c4f27e8383db 100644 (file)
--- a/test/Transforms/InstCombine/loadstore-metadata.ll
+++ b/test/Transforms/InstCombine/loadstore-metadata.ll
@@ -1,5 +1,7 @@
 ; RUN: opt -instcombine -S < %s | FileCheck %s
 
+target datalayout = "e-m:e-p:64:64:64-i64:64-f80:128-n8:16:32:64-S128"
+
 define i32 @test_load_cast_combine_tbaa(float* %ptr) {
 ; Ensure (cast (load (...))) -> (load (cast (...))) preserves TBAA.
 ; CHECK-LABEL: @test_load_cast_combine_tbaa(