Disable -fmerge-all-constants as default.

Summary:
"-fmerge-all-constants" is a non-conforming optimization and should not
be the default. It is also causing miscompiles when building Linux
Kernel (https://lkml.org/lkml/2018/3/20/872).

Fixes PR18538.

Reviewers: rjmccall, rsmith, chandlerc

Reviewed By: rsmith, chandlerc

Subscribers: srhines, cfe-commits

Differential Revision: https://reviews.llvm.org/D45289

llvm-svn: 329300

7 files changed, 21 insertions, 10 deletions

diff --git a/clang/test/CodeGen/array-init.c b/clang/test/CodeGen/array-init.c
index fa54994acc3..62e87edc297 100644
--- a/clang/test/CodeGen/array-init.c
+++ b/clang/test/CodeGen/array-init.c
@@ -1,8 +1,11 @@
-// RUN: %clang_cc1 %s -O0 -triple x86_64-unknown-linux-gnu -emit-llvm -o - | FileCheck %s
+// RUN: %clang_cc1 %s -O0 -triple x86_64-unknown-linux-gnu -emit-llvm -o - | FileCheck -check-prefix=CHECK-NO-MERGE-CONSTANTS %s
+// RUN: %clang_cc1 %s -O0 -triple x86_64-unknown-linux-gnu -fmerge-all-constants -emit-llvm -o - | FileCheck -check-prefix=CHECK-MERGE-CONSTANTS %s
 
-// CHECK: @{{.*}}.a1 = internal constant [5 x i32] [i32 0, i32 1, i32 2, i32 0, i32 0]
-// CHECK: @{{.*}}.a2 = internal constant [5 x i32] zeroinitializer
-// CHECK: @{{.*}}.a3 = internal constant [5 x i32] zeroinitializer
+// CHECK-NO-MERGE-CONSTANTS: @{{.*}}.a1 = private unnamed_addr constant [5 x i32] [i32 0, i32 1, i32 2, i32 0, i32 0]
+
+// CHECK-MERGE-CONSTANTS: @{{.*}}.a1 = internal constant [5 x i32] [i32 0, i32 1, i32 2, i32 0, i32 0]
+// CHECK-MERGE-CONSTANTS: @{{.*}}.a2 = internal constant [5 x i32] zeroinitializer
+// CHECK-MERGE-CONSTANTS: @{{.*}}.a3 = internal constant [5 x i32] zeroinitializer
 
 void testConstArrayInits(void)
 {
diff --git a/clang/test/CodeGen/decl.c b/clang/test/CodeGen/decl.c
index ffee1e3cef1..d62629c7fb5 100644
--- a/clang/test/CodeGen/decl.c
+++ b/clang/test/CodeGen/decl.c
@@ -1,4 +1,4 @@
-// RUN: %clang_cc1 -w -emit-llvm < %s | FileCheck %s
+// RUN: %clang_cc1 -w -fmerge-all-constants -emit-llvm < %s | FileCheck %s
 
 // CHECK: @test1.x = internal constant [12 x i32] [i32 1
 // CHECK: @test2.x = private unnamed_addr constant [13 x i32] [i32 1,
diff --git a/clang/test/CodeGenCXX/const-init-cxx11.cpp b/clang/test/CodeGenCXX/const-init-cxx11.cpp
index c4962bc08ad..801d7b1e19c 100644
--- a/clang/test/CodeGenCXX/const-init-cxx11.cpp
+++ b/clang/test/CodeGenCXX/const-init-cxx11.cpp
@@ -1,4 +1,4 @@
-// RUN: %clang_cc1 -w -triple x86_64-elf-gnu -emit-llvm -o - %s -std=c++11 | FileCheck %s
+// RUN: %clang_cc1 -w -fmerge-all-constants -triple x86_64-elf-gnu -emit-llvm -o - %s -std=c++11 | FileCheck %s
 
 // FIXME: The padding in all these objects should be zero-initialized.
 namespace StructUnion {
diff --git a/clang/test/CodeGenCXX/cxx0x-initializer-references.cpp b/clang/test/CodeGenCXX/cxx0x-initializer-references.cpp
index 318c8ea0d77..595d27ca2e8 100644
--- a/clang/test/CodeGenCXX/cxx0x-initializer-references.cpp
+++ b/clang/test/CodeGenCXX/cxx0x-initializer-references.cpp
@@ -1,4 +1,4 @@
-// RUN: %clang_cc1 -std=c++11 -S -triple armv7-none-eabi -emit-llvm -o - %s | FileCheck %s
+// RUN: %clang_cc1 -std=c++11 -S -triple armv7-none-eabi -fmerge-all-constants -emit-llvm -o - %s | FileCheck %s
 
 namespace reference {
   struct A {
diff --git a/clang/test/CodeGenCXX/cxx0x-initializer-stdinitializerlist.cpp b/clang/test/CodeGenCXX/cxx0x-initializer-stdinitializerlist.cpp
index e1c18169a8a..3299763997e 100644
--- a/clang/test/CodeGenCXX/cxx0x-initializer-stdinitializerlist.cpp
+++ b/clang/test/CodeGenCXX/cxx0x-initializer-stdinitializerlist.cpp
@@ -1,5 +1,5 @@
-// RUN: %clang_cc1 -std=c++11 -triple x86_64-none-linux-gnu -emit-llvm -o - %s | FileCheck -check-prefixes=X86,CHECK %s
-// RUN: %clang_cc1 -std=c++11 -triple amdgcn-amd-amdhsa -DNO_TLS -emit-llvm -o - %s | FileCheck -check-prefixes=AMDGCN,CHECK %s
+// RUN: %clang_cc1 -std=c++11 -triple x86_64-none-linux-gnu -fmerge-all-constants -emit-llvm -o - %s | FileCheck -check-prefixes=X86,CHECK %s
+// RUN: %clang_cc1 -std=c++11 -triple amdgcn-amd-amdhsa -DNO_TLS -fmerge-all-constants -emit-llvm -o - %s | FileCheck -check-prefixes=AMDGCN,CHECK %s
 
 namespace std {
   typedef decltype(sizeof(int)) size_t;
diff --git a/clang/test/CodeGenObjCXX/arc-cxx11-init-list.mm b/clang/test/CodeGenObjCXX/arc-cxx11-init-list.mm
index c3723c619ab..af607654e15 100644
--- a/clang/test/CodeGenObjCXX/arc-cxx11-init-list.mm
+++ b/clang/test/CodeGenObjCXX/arc-cxx11-init-list.mm
@@ -1,4 +1,4 @@
-// RUN: %clang_cc1 -triple armv7-ios5.0 -std=c++11 -fobjc-arc -Os -emit-llvm -o - %s | FileCheck %s
+// RUN: %clang_cc1 -triple armv7-ios5.0 -std=c++11 -fmerge-all-constants -fobjc-arc -Os -emit-llvm -o - %s | FileCheck %s
 
 // CHECK: @[[STR0:.*]] = private unnamed_addr constant [5 x i8] c"str0\00", section "__TEXT,__cstring,cstring_literals"
 // CHECK: @[[UNNAMED_CFSTRING0:.*]] = private global %struct.__NSConstantString_tag { i32* getelementptr inbounds ([0 x i32], [0 x i32]* @__CFConstantStringClassReference, i32 0, i32 0), i32 1992, i8* getelementptr inbounds ([5 x i8], [5 x i8]* @[[STR0]], i32 0, i32 0), i32 4 }, section "__DATA,__cfstring"
diff --git a/clang/test/Driver/clang_f_opts.c b/clang/test/Driver/clang_f_opts.c
index 9c90f0e58f4..2b2a7e7b98f 100644
--- a/clang/test/Driver/clang_f_opts.c
+++ b/clang/test/Driver/clang_f_opts.c
@@ -276,6 +276,7 @@
 // RUN:     -fno-inline-small-functions -finline-small-functions              \
 // RUN:     -fno-fat-lto-objects -ffat-lto-objects                            \
 // RUN:     -fno-merge-constants -fmerge-constants                            \
+// RUN:     -fno-merge-all-constants -fmerge-all-constants                    \
 // RUN:     -fno-caller-saves -fcaller-saves                                  \
 // RUN:     -fno-reorder-blocks -freorder-blocks                              \
 // RUN:     -fno-schedule-insns2 -fschedule-insns2                            \
@@ -522,3 +523,10 @@
 // RUN: %clang -### -S -fno-discard-value-names %s 2>&1 | FileCheck -check-prefix=CHECK-NO-DISCARD-NAMES %s
 // CHECK-DISCARD-NAMES: "-discard-value-names"
 // CHECK-NO-DISCARD-NAMES-NOT: "-discard-value-names"
+//
+// RUN: %clang -### -S -fmerge-all-constants %s 2>&1 | FileCheck -check-prefix=CHECK-MERGE-ALL-CONSTANTS %s
+// RUN: %clang -### -S -fno-merge-all-constants %s 2>&1 | FileCheck -check-prefix=CHECK-NO-MERGE-ALL-CONSTANTS %s
+// RUN: %clang -### -S -fmerge-all-constants -fno-merge-all-constants %s 2>&1 | FileCheck -check-prefix=CHECK-NO-MERGE-ALL-CONSTANTS %s
+// RUN: %clang -### -S -fno-merge-all-constants -fmerge-all-constants %s 2>&1 | FileCheck -check-prefix=CHECK-MERGE-ALL-CONSTANTS %s
+// CHECK-NO-MERGE-ALL-CONSTANTS-NOT: "-fmerge-all-constants"
+// CHECK-MERGE-ALL-CONSTANTS: "-fmerge-all-constants"