1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
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"}
|
