From: Manoj Gupta Date: Thu, 5 Apr 2018 15:29:52 +0000 (+0000) Subject: Disable -fmerge-all-constants as default. X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=abb490ec962c6db7c2071ba9d1bd0cd60b4a1b3a;p=clang 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 git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@329300 91177308-0d34-0410-b5e6-96231b3b80d8 --- diff --git a/include/clang/Driver/Options.td b/include/clang/Driver/Options.td index abec5edddf..c72bb39ec5 100644 --- a/include/clang/Driver/Options.td +++ b/include/clang/Driver/Options.td @@ -1133,7 +1133,8 @@ def fthinlto_index_EQ : Joined<["-"], "fthinlto-index=">, HelpText<"Perform ThinLTO importing using provided function summary index">; def fmacro_backtrace_limit_EQ : Joined<["-"], "fmacro-backtrace-limit=">, Group, Flags<[DriverOption, CoreOption]>; -def fmerge_all_constants : Flag<["-"], "fmerge-all-constants">, Group; +def fmerge_all_constants : Flag<["-"], "fmerge-all-constants">, Group, + Flags<[CC1Option]>, HelpText<"Allow merging of constants">; def fmessage_length_EQ : Joined<["-"], "fmessage-length=">, Group; def fms_extensions : Flag<["-"], "fms-extensions">, Group, Flags<[CC1Option, CoreOption]>, HelpText<"Accept some non-standard constructs supported by the Microsoft compiler">; @@ -1282,7 +1283,7 @@ def fveclib : Joined<["-"], "fveclib=">, Group, Flags<[CC1Option]>, def fno_lax_vector_conversions : Flag<["-"], "fno-lax-vector-conversions">, Group, HelpText<"Disallow implicit conversions between vectors with a different number of elements or different element types">, Flags<[CC1Option]>; def fno_merge_all_constants : Flag<["-"], "fno-merge-all-constants">, Group, - Flags<[CC1Option]>, HelpText<"Disallow merging of constants">; + HelpText<"Disallow merging of constants">; def fno_modules : Flag <["-"], "fno-modules">, Group, Flags<[DriverOption]>; def fno_implicit_module_maps : Flag <["-"], "fno-implicit-module-maps">, Group, diff --git a/lib/AST/ExprConstant.cpp b/lib/AST/ExprConstant.cpp index 6de55f10dc..4725b1b569 100644 --- a/lib/AST/ExprConstant.cpp +++ b/lib/AST/ExprConstant.cpp @@ -8596,9 +8596,6 @@ bool IntExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) { (LHSValue.Base && isZeroSized(RHSValue))) return Error(E); // Pointers with different bases cannot represent the same object. - // (Note that clang defaults to -fmerge-all-constants, which can - // lead to inconsistent results for comparisons involving the address - // of a constant; this generally doesn't matter in practice.) return Success(E->getOpcode() == BO_NE, E); } diff --git a/lib/Driver/ToolChains/Clang.cpp b/lib/Driver/ToolChains/Clang.cpp index a86c5376e4..8e11e872d4 100644 --- a/lib/Driver/ToolChains/Clang.cpp +++ b/lib/Driver/ToolChains/Clang.cpp @@ -3361,9 +3361,9 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA, Args.AddLastArg(CmdArgs, options::OPT_fveclib); - if (!Args.hasFlag(options::OPT_fmerge_all_constants, - options::OPT_fno_merge_all_constants)) - CmdArgs.push_back("-fno-merge-all-constants"); + if (Args.hasFlag(options::OPT_fmerge_all_constants, + options::OPT_fno_merge_all_constants, false)) + CmdArgs.push_back("-fmerge-all-constants"); // LLVM Code Generator Options. diff --git a/lib/Frontend/CompilerInvocation.cpp b/lib/Frontend/CompilerInvocation.cpp index 734349eed7..45546ac3bc 100644 --- a/lib/Frontend/CompilerInvocation.cpp +++ b/lib/Frontend/CompilerInvocation.cpp @@ -605,7 +605,7 @@ static bool ParseCodeGenArgs(CodeGenOptions &Opts, ArgList &Args, InputKind IK, Args.hasFlag(OPT_ffine_grained_bitfield_accesses, OPT_fno_fine_grained_bitfield_accesses, false); Opts.DwarfDebugFlags = Args.getLastArgValue(OPT_dwarf_debug_flags); - Opts.MergeAllConstants = !Args.hasArg(OPT_fno_merge_all_constants); + Opts.MergeAllConstants = Args.hasArg(OPT_fmerge_all_constants); Opts.NoCommon = Args.hasArg(OPT_fno_common); Opts.NoImplicitFloat = Args.hasArg(OPT_no_implicit_float); Opts.OptimizeSize = getOptimizationLevelSize(Args); diff --git a/test/CodeGen/array-init.c b/test/CodeGen/array-init.c index fa54994acc..62e87edc29 100644 --- a/test/CodeGen/array-init.c +++ b/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/test/CodeGen/decl.c b/test/CodeGen/decl.c index ffee1e3cef..d62629c7fb 100644 --- a/test/CodeGen/decl.c +++ b/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/test/CodeGenCXX/const-init-cxx11.cpp b/test/CodeGenCXX/const-init-cxx11.cpp index c4962bc08a..801d7b1e19 100644 --- a/test/CodeGenCXX/const-init-cxx11.cpp +++ b/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/test/CodeGenCXX/cxx0x-initializer-references.cpp b/test/CodeGenCXX/cxx0x-initializer-references.cpp index 318c8ea0d7..595d27ca2e 100644 --- a/test/CodeGenCXX/cxx0x-initializer-references.cpp +++ b/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/test/CodeGenCXX/cxx0x-initializer-stdinitializerlist.cpp b/test/CodeGenCXX/cxx0x-initializer-stdinitializerlist.cpp index e1c18169a8..3299763997 100644 --- a/test/CodeGenCXX/cxx0x-initializer-stdinitializerlist.cpp +++ b/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/test/CodeGenObjCXX/arc-cxx11-init-list.mm b/test/CodeGenObjCXX/arc-cxx11-init-list.mm index c3723c619a..af607654e1 100644 --- a/test/CodeGenObjCXX/arc-cxx11-init-list.mm +++ b/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/test/Driver/clang_f_opts.c b/test/Driver/clang_f_opts.c index 9c90f0e58f..2b2a7e7b98 100644 --- a/test/Driver/clang_f_opts.c +++ b/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"