1 files changed, 107 insertions, 0 deletions
diff --git a/patches/llvm_host/llvm-0008-dont-widen-metadata-on-store-to-load-forwarding.patch b/patches/llvm_host/llvm-0008-dont-widen-metadata-on-store-to-load-forwarding.patch
new file mode 100644
index 00000000..b66584dc
--- /dev/null
+++ b/patches/llvm_host/llvm-0008-dont-widen-metadata-on-store-to-load-forwarding.patch
@@ -0,0 +1,107 @@
+From 3c80c2658022201214241e9229ac35097cc476d2 Mon Sep 17 00:00:00 2001
+From: Eli Friedman <eli.friedman@gmail.com>
+Date: Thu, 16 Jun 2016 02:33:42 +0000
+Subject: [PATCH] [InstCombine] Don't widen metadata on store-to-load
+ forwarding
+
+The original check for load CSE or store-to-load forwarding is wrong
+when the forwarded stored value happened to be a load.
+
+Ref https://github.com/JuliaLang/julia/issues/16894
+
+Differential Revision: http://reviews.llvm.org/D21271
+
+Patch by Yichao Yu!
+
+git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@272868 91177308-0d34-0410-b5e6-96231b3b80d8
+
+Alpine maintainer notes:
+  - Updated for llvm 3.8.1.
+  - Corresponds to llvm-D21271-instcombine-tbaa-3.8.patch in Julia.
+---
+ include/llvm/Analysis/Loads.h                           |  3 ++-
+ lib/Analysis/Loads.cpp                                  |  5 ++++-
+ .../InstCombine/InstCombineLoadStoreAlloca.cpp          |  6 ++++--
+ test/Transforms/InstCombine/tbaa-store-to-load.ll       | 17 +++++++++++++++++
+ 4 files changed, 27 insertions(+), 4 deletions(-)
+ create mode 100644 test/Transforms/InstCombine/tbaa-store-to-load.ll
+
+diff --git a/include/llvm/Analysis/Loads.h b/include/llvm/Analysis/Loads.h
+index e5bd0c8..9d24b7b 100644
+--- a/include/llvm/Analysis/Loads.h
++++ b/include/llvm/Analysis/Loads.h
+@@ -82,7 +82,8 @@ Value *FindAvailableLoadedValue(LoadInst *Load, BasicBlock *ScanBB,
+                                 BasicBlock::iterator &ScanFrom,
+                                 unsigned MaxInstsToScan = DefMaxInstsToScan,
+                                 AliasAnalysis *AA = nullptr,
+-                                AAMDNodes *AATags = nullptr);
++                                AAMDNodes *AATags = nullptr,
++                                bool *IsLoadCSE = nullptr);
+ 
+ }
+ 
+diff --git a/lib/Analysis/Loads.cpp b/lib/Analysis/Loads.cpp
+index dce243c..7d3fd59 100644
+--- a/lib/Analysis/Loads.cpp
++++ b/lib/Analysis/Loads.cpp
+@@ -322,7 +322,8 @@ llvm::DefMaxInstsToScan("available-load-scan-limit", cl::init(6), cl::Hidden,
+ Value *llvm::FindAvailableLoadedValue(LoadInst *Load, BasicBlock *ScanBB,
+                                       BasicBlock::iterator &ScanFrom,
+                                       unsigned MaxInstsToScan,
+-                                      AliasAnalysis *AA, AAMDNodes *AATags) {
++                                      AliasAnalysis *AA, AAMDNodes *AATags,
++                                      bool *IsLoadCSE) {
+   if (MaxInstsToScan == 0)
+     MaxInstsToScan = ~0U;
+ 
+@@ -374,6 +375,8 @@ Value *llvm::FindAvailableLoadedValue(LoadInst *Load, BasicBlock *ScanBB,
+ 
+         if (AATags)
+           LI->getAAMetadata(*AATags);
++        if (IsLoadCSE)
++            *IsLoadCSE = true;
+         return LI;
+       }
+ 
+diff --git a/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp b/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp
+index 6a5d5a6..d312983 100644
+--- a/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp
++++ b/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp
+@@ -800,10 +800,12 @@ Instruction *InstCombiner::visitLoadInst(LoadInst &LI) {
+   // separated by a few arithmetic operations.
+   BasicBlock::iterator BBI(LI);
+   AAMDNodes AATags;
++  bool IsLoadCSE = false;
+   if (Value *AvailableVal =
+       FindAvailableLoadedValue(Op, LI.getParent(), BBI,
+-                               DefMaxInstsToScan, AA, &AATags)) {
+-    if (LoadInst *NLI = dyn_cast<LoadInst>(AvailableVal)) {
++                               DefMaxInstsToScan, AA, &AATags, &IsLoadCSE)) {
++    if (IsLoadCSE) {
++      LoadInst *NLI = cast<LoadInst>(AvailableVal);
+       unsigned KnownIDs[] = {
+           LLVMContext::MD_tbaa,            LLVMContext::MD_alias_scope,
+           LLVMContext::MD_noalias, LLVMContext::MD_range,
+diff --git a/test/Transforms/InstCombine/tbaa-store-to-load.ll b/test/Transforms/InstCombine/tbaa-store-to-load.ll
+new file mode 100644
+index 0000000..707be73
+--- /dev/null
++++ b/test/Transforms/InstCombine/tbaa-store-to-load.ll
+@@ -0,0 +1,17 @@
++; RUN: opt -S -instcombine < %s 2>&1 | FileCheck %s
++
++define i64 @f(i64* %p1, i64* %p2) {
++top:
++  ; check that the tbaa is preserved
++  ; CHECK-LABEL: @f(
++  ; CHECK: %v1 = load i64, i64* %p1, align 8, !tbaa !0
++  ; CHECK: store i64 %v1, i64* %p2, align 8
++  ; CHECK: ret i64 %v1
++  %v1 = load i64, i64* %p1, align 8, !tbaa !0
++  store i64 %v1, i64* %p2, align 8
++  %v2 = load i64, i64* %p2, align 8
++  ret i64 %v2
++}
++
++!0 = !{!1, !1, i64 0}
++!1 = !{!"load_tbaa"}