[clang] [clang] Make -fveclib={ArmPL, SLEEF} imply -fno-math-errno (PR #112580)
Benjamin Maxwell via cfe-commits
cfe-commits at lists.llvm.org
Thu Oct 17 10:36:08 PDT 2024
https://github.com/MacDue updated https://github.com/llvm/llvm-project/pull/112580
>From d8ac47d27ad860a8b11424621ab88cd9267cf866 Mon Sep 17 00:00:00 2001
From: Benjamin Maxwell <benjamin.maxwell at arm.com>
Date: Wed, 2 Oct 2024 10:28:29 +0000
Subject: [PATCH 1/3] [clang] Make -fveclib={ArmPL,SLEEF} imply -fno-math-errno
These two veclibs are only available for AArch64 targets, and as
mentioned in https://discourse.llvm.org/t/rfc-should-fveclib-imply-fno-math-errno-for-all-targets/81384,
we (Arm) think that `-fveclib` should imply `-fno-math-errno`. By
setting `-fveclib` the user shows they intend to use the vector math
functions, which implies they don't care about errno. However,
currently, the vector mappings won't be used in many cases without
setting `-fno-math-errno` separately.
Making this change would also help resolve some inconsistencies in how
vector mappings are applied (see https://github.com/llvm/llvm-project/pull/108980#discussion_r1766555560).
---
clang/include/clang/Driver/Options.td | 3 ++-
clang/lib/Driver/ToolChains/Clang.cpp | 8 ++++++++
clang/test/Driver/fveclib.c | 7 +++++++
3 files changed, 17 insertions(+), 1 deletion(-)
diff --git a/clang/include/clang/Driver/Options.td b/clang/include/clang/Driver/Options.td
index 379e75b197cf96..7965f70e290408 100644
--- a/clang/include/clang/Driver/Options.td
+++ b/clang/include/clang/Driver/Options.td
@@ -3410,7 +3410,8 @@ def fno_experimental_isel : Flag<["-"], "fno-experimental-isel">, Group<f_clang_
Alias<fno_global_isel>;
def fveclib : Joined<["-"], "fveclib=">, Group<f_Group>,
Visibility<[ClangOption, CC1Option, FlangOption, FC1Option]>,
- HelpText<"Use the given vector functions library">,
+ HelpText<"Use the given vector functions library."
+ "Note: -fveclib={ArmPL,SLEEF} implies -fno-math-errno">,
Values<"Accelerate,libmvec,MASSV,SVML,SLEEF,Darwin_libsystem_m,ArmPL,AMDLIBM,none">,
NormalizedValuesScope<"llvm::driver::VectorLibrary">,
NormalizedValues<["Accelerate", "LIBMVEC", "MASSV", "SVML", "SLEEF",
diff --git a/clang/lib/Driver/ToolChains/Clang.cpp b/clang/lib/Driver/ToolChains/Clang.cpp
index 3fc39296f44281..7e7f3770cfb62d 100644
--- a/clang/lib/Driver/ToolChains/Clang.cpp
+++ b/clang/lib/Driver/ToolChains/Clang.cpp
@@ -2854,6 +2854,10 @@ static void RenderFloatingPointOptions(const ToolChain &TC, const Driver &D,
bool OFastEnabled, const ArgList &Args,
ArgStringList &CmdArgs,
const JobAction &JA) {
+ // List of veclibs which when used with -fveclib imply -fno-math-errno.
+ constexpr std::array VecLibImpliesNoMathErrno{llvm::StringLiteral("ArmPL"),
+ llvm::StringLiteral("SLEEF")};
+
// Handle various floating point optimization flags, mapping them to the
// appropriate LLVM code generation flags. This is complicated by several
// "umbrella" flags, so we do this by stepping through the flags incrementally
@@ -3125,6 +3129,10 @@ static void RenderFloatingPointOptions(const ToolChain &TC, const Driver &D,
TrappingMathPresent = true;
FPExceptionBehavior = "strict";
break;
+ case options::OPT_fveclib:
+ if (llvm::is_contained(VecLibImpliesNoMathErrno, A->getValue()))
+ MathErrno = false;
+ break;
case options::OPT_fno_trapping_math:
if (!TrappingMathPresent && !FPExceptionBehavior.empty() &&
FPExceptionBehavior != "ignore")
diff --git a/clang/test/Driver/fveclib.c b/clang/test/Driver/fveclib.c
index 9b0f1ce13aa2bd..2a3133541e3b72 100644
--- a/clang/test/Driver/fveclib.c
+++ b/clang/test/Driver/fveclib.c
@@ -36,16 +36,23 @@
/* Verify that the correct vector library is passed to LTO flags. */
// RUN: %clang -### --target=x86_64-unknown-linux-gnu -fveclib=LIBMVEC -flto %s 2>&1 | FileCheck --check-prefix=CHECK-LTO-LIBMVEC %s
+// CHECK-LTO-LIBMVEC: "-fmath-errno"
// CHECK-LTO-LIBMVEC: "-plugin-opt=-vector-library=LIBMVEC-X86"
// RUN: %clang -### --target=powerpc64-unknown-linux-gnu -fveclib=MASSV -flto %s 2>&1 | FileCheck --check-prefix=CHECK-LTO-MASSV %s
+// CHECK-LTO-MASSV: "-fmath-errno"
// CHECK-LTO-MASSV: "-plugin-opt=-vector-library=MASSV"
// RUN: %clang -### --target=x86_64-unknown-linux-gnu -fveclib=SVML -flto %s 2>&1 | FileCheck --check-prefix=CHECK-LTO-SVML %s
+// CHECK-LTO-SVML: "-fmath-errno"
// CHECK-LTO-SVML: "-plugin-opt=-vector-library=SVML"
// RUN: %clang -### --target=aarch64-linux-gnu -fveclib=SLEEF -flto %s 2>&1 | FileCheck --check-prefix=CHECK-LTO-SLEEF %s
+// CHECK-LTO-SLEEF-NOT: "-fmath-errno"
// CHECK-LTO-SLEEF: "-plugin-opt=-vector-library=sleefgnuabi"
+// CHECK-LTO-SLEEF-NOT: "-fmath-errno"
// RUN: %clang -### --target=aarch64-linux-gnu -fveclib=ArmPL -flto %s 2>&1 | FileCheck --check-prefix=CHECK-LTO-ARMPL %s
+// CHECK-LTO-ARMPL-NOT: "-fmath-errno"
// CHECK-LTO-ARMPL: "-plugin-opt=-vector-library=ArmPL"
+// CHECK-LTO-ARMPL-NOT: "-fmath-errno"
>From 75bcb5480909f3b6554836d95063346758615d4c Mon Sep 17 00:00:00 2001
From: Benjamin Maxwell <benjamin.maxwell at arm.com>
Date: Thu, 17 Oct 2024 14:54:53 +0000
Subject: [PATCH 2/3] Fixups and tests
---
clang/include/clang/Driver/Options.td | 2 +-
clang/test/Driver/fveclib.c | 40 ++++++++++++++++++++++-----
2 files changed, 34 insertions(+), 8 deletions(-)
diff --git a/clang/include/clang/Driver/Options.td b/clang/include/clang/Driver/Options.td
index 7965f70e290408..d1c0d1080cf5ed 100644
--- a/clang/include/clang/Driver/Options.td
+++ b/clang/include/clang/Driver/Options.td
@@ -3411,7 +3411,7 @@ def fno_experimental_isel : Flag<["-"], "fno-experimental-isel">, Group<f_clang_
def fveclib : Joined<["-"], "fveclib=">, Group<f_Group>,
Visibility<[ClangOption, CC1Option, FlangOption, FC1Option]>,
HelpText<"Use the given vector functions library."
- "Note: -fveclib={ArmPL,SLEEF} implies -fno-math-errno">,
+ "Note: In clang -fveclib={ArmPL,SLEEF} implies -fno-math-errno">,
Values<"Accelerate,libmvec,MASSV,SVML,SLEEF,Darwin_libsystem_m,ArmPL,AMDLIBM,none">,
NormalizedValuesScope<"llvm::driver::VectorLibrary">,
NormalizedValues<["Accelerate", "LIBMVEC", "MASSV", "SVML", "SLEEF",
diff --git a/clang/test/Driver/fveclib.c b/clang/test/Driver/fveclib.c
index 2a3133541e3b72..797b7b2a03d456 100644
--- a/clang/test/Driver/fveclib.c
+++ b/clang/test/Driver/fveclib.c
@@ -36,23 +36,49 @@
/* Verify that the correct vector library is passed to LTO flags. */
// RUN: %clang -### --target=x86_64-unknown-linux-gnu -fveclib=LIBMVEC -flto %s 2>&1 | FileCheck --check-prefix=CHECK-LTO-LIBMVEC %s
-// CHECK-LTO-LIBMVEC: "-fmath-errno"
// CHECK-LTO-LIBMVEC: "-plugin-opt=-vector-library=LIBMVEC-X86"
// RUN: %clang -### --target=powerpc64-unknown-linux-gnu -fveclib=MASSV -flto %s 2>&1 | FileCheck --check-prefix=CHECK-LTO-MASSV %s
-// CHECK-LTO-MASSV: "-fmath-errno"
// CHECK-LTO-MASSV: "-plugin-opt=-vector-library=MASSV"
// RUN: %clang -### --target=x86_64-unknown-linux-gnu -fveclib=SVML -flto %s 2>&1 | FileCheck --check-prefix=CHECK-LTO-SVML %s
-// CHECK-LTO-SVML: "-fmath-errno"
// CHECK-LTO-SVML: "-plugin-opt=-vector-library=SVML"
// RUN: %clang -### --target=aarch64-linux-gnu -fveclib=SLEEF -flto %s 2>&1 | FileCheck --check-prefix=CHECK-LTO-SLEEF %s
-// CHECK-LTO-SLEEF-NOT: "-fmath-errno"
// CHECK-LTO-SLEEF: "-plugin-opt=-vector-library=sleefgnuabi"
-// CHECK-LTO-SLEEF-NOT: "-fmath-errno"
// RUN: %clang -### --target=aarch64-linux-gnu -fveclib=ArmPL -flto %s 2>&1 | FileCheck --check-prefix=CHECK-LTO-ARMPL %s
-// CHECK-LTO-ARMPL-NOT: "-fmath-errno"
// CHECK-LTO-ARMPL: "-plugin-opt=-vector-library=ArmPL"
-// CHECK-LTO-ARMPL-NOT: "-fmath-errno"
+
+
+/* Verify that -fmath-errno is set correctly for the vector library. */
+
+// RUN: %clang -### --target=x86_64-unknown-linux-gnu -fveclib=LIBMVEC %s 2>&1 | FileCheck --check-prefix=CHECK-ERRNO-LIBMVEC %s
+// CHECK-ERRNO-LIBMVEC: "-fveclib=LIBMVEC"
+// CHECK-ERRNO-LIBMVEC-SAME: "-fmath-errno"
+
+// RUN: %clang -### --target=powerpc64-unknown-linux-gnu -fveclib=MASSV %s 2>&1 | FileCheck --check-prefix=CHECK-ERRNO-MASSV %s
+// CHECK-ERRNO-MASSV: "-fveclib=MASSV"
+// CHECK-ERRNO-MASSV-SAME: "-fmath-errno"
+
+// RUN: %clang -### --target=x86_64-unknown-linux-gnu -fveclib=SVML %s 2>&1 | FileCheck --check-prefix=CHECK-ERRNO-SVML %s
+// CHECK-ERRNO-SVML: "-fveclib=SVML"
+// CHECK-ERRNO-SVML-SAME: "-fmath-errno"
+
+// RUN: %clang -### --target=aarch64-linux-gnu -fveclib=SLEEF %s 2>&1 | FileCheck --check-prefix=CHECK-ERRNO-SLEEF %s
+// CHECK-ERRNO-SLEEF-NOT: "-fmath-errno"
+// CHECK-ERRNO-SLEEF: "-fveclib=SLEEF"
+// CHECK-ERRNO-SLEEF-NOT: "-fmath-errno"
+
+// RUN: %clang -### --target=aarch64-linux-gnu -fveclib=ArmPL %s 2>&1 | FileCheck --check-prefix=CHECK-ERRNO-ARMPL %s
+// CHECK-ERRNO-ARMPL-NOT: "-fmath-errno"
+// CHECK-ERRNO-ARMPL: "-fveclib=ArmPL"
+// CHECK-ERRNO-ARMPL-NOT: "-fmath-errno"
+
+// RUN: %clang -### --target=aarch64-linux-gnu -fveclib=ArmPL -fmath-errno %s 2>&1 | FileCheck --check-prefix=CHECK-FORCE-ERRNO-ARMPL %s
+// CHECK-FORCE-ERRNO-ARMPL: "-fveclib=ArmPL"
+// CHECK-FORCE-ERRNO-ARMPL-SAME: "-fmath-errno"
+
+// RUN: %clang -### --target=aarch64-linux-gnu -fveclib=SLEEF -fmath-errno %s 2>&1 | FileCheck --check-prefix=CHECK-FORCE-ERRNO-SLEEF %s
+// CHECK-FORCE-ERRNO-SLEEF: "-fveclib=SLEEF"
+// CHECK-FORCE-ERRNO-SLEEF-SAME: "-fmath-errno"
>From 1e01038a50c324d1465ac70ec18ba940b0778fa6 Mon Sep 17 00:00:00 2001
From: Benjamin Maxwell <benjamin.maxwell at arm.com>
Date: Thu, 17 Oct 2024 17:34:35 +0000
Subject: [PATCH 3/3] Add clang warning
---
.../clang/Basic/DiagnosticDriverKinds.td | 3 +++
clang/lib/Driver/ToolChains/Clang.cpp | 23 ++++++++++++++--
clang/test/Driver/fveclib.c | 26 ++++++++++++++-----
3 files changed, 43 insertions(+), 9 deletions(-)
diff --git a/clang/include/clang/Basic/DiagnosticDriverKinds.td b/clang/include/clang/Basic/DiagnosticDriverKinds.td
index 68722ad9633120..e0c188f78a7806 100644
--- a/clang/include/clang/Basic/DiagnosticDriverKinds.td
+++ b/clang/include/clang/Basic/DiagnosticDriverKinds.td
@@ -502,6 +502,9 @@ def err_sls_hardening_arm_not_supported : Error<
def warn_drv_large_data_threshold_invalid_code_model: Warning<
"'%0' only applies to medium and large code models">,
InGroup<UnusedCommandLineArgument>;
+def warn_drv_math_errno_reenabled_after_veclib: Warning<
+ "math errno re-enabled by '%0' after it was implicitly disabled by '%1',"
+ " this may prevent vectorization with the specified vector library">;
def note_drv_command_failed_diag_msg : Note<
"diagnostic msg: %0">;
diff --git a/clang/lib/Driver/ToolChains/Clang.cpp b/clang/lib/Driver/ToolChains/Clang.cpp
index 7e7f3770cfb62d..98a60ad2bcee8c 100644
--- a/clang/lib/Driver/ToolChains/Clang.cpp
+++ b/clang/lib/Driver/ToolChains/Clang.cpp
@@ -41,6 +41,7 @@
#include "clang/Driver/SanitizerArgs.h"
#include "clang/Driver/Types.h"
#include "clang/Driver/XRayArgs.h"
+#include "llvm/ADT/ScopeExit.h"
#include "llvm/ADT/SmallSet.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/BinaryFormat/Magic.h"
@@ -2857,6 +2858,10 @@ static void RenderFloatingPointOptions(const ToolChain &TC, const Driver &D,
// List of veclibs which when used with -fveclib imply -fno-math-errno.
constexpr std::array VecLibImpliesNoMathErrno{llvm::StringLiteral("ArmPL"),
llvm::StringLiteral("SLEEF")};
+ bool NoMathErrnoWasImpliedByVeclib = false;
+ const Arg *VeclibArg = nullptr;
+ // Track the arg (if any) that reenabled errno after -fveclib for diagnostics.
+ const Arg *ArgThatReenabledMathErrnoAfterVeclib = nullptr;
// Handle various floating point optimization flags, mapping them to the
// appropriate LLVM code generation flags. This is complicated by several
@@ -2964,6 +2969,12 @@ static void RenderFloatingPointOptions(const ToolChain &TC, const Driver &D,
}
for (const Arg *A : Args) {
+ auto CheckMathErrnoForVeclib =
+ llvm::make_scope_exit([&, MathErrnoBeforeArg = MathErrno] {
+ if (NoMathErrnoWasImpliedByVeclib && !MathErrnoBeforeArg && MathErrno)
+ ArgThatReenabledMathErrnoAfterVeclib = A;
+ });
+
switch (A->getOption().getID()) {
// If this isn't an FP option skip the claim below
default: continue;
@@ -3130,8 +3141,11 @@ static void RenderFloatingPointOptions(const ToolChain &TC, const Driver &D,
FPExceptionBehavior = "strict";
break;
case options::OPT_fveclib:
- if (llvm::is_contained(VecLibImpliesNoMathErrno, A->getValue()))
+ if (llvm::is_contained(VecLibImpliesNoMathErrno, A->getValue())) {
MathErrno = false;
+ NoMathErrnoWasImpliedByVeclib = true;
+ VeclibArg = A;
+ }
break;
case options::OPT_fno_trapping_math:
if (!TrappingMathPresent && !FPExceptionBehavior.empty() &&
@@ -3346,8 +3360,13 @@ static void RenderFloatingPointOptions(const ToolChain &TC, const Driver &D,
if (ApproxFunc)
CmdArgs.push_back("-fapprox-func");
- if (MathErrno)
+ if (MathErrno) {
CmdArgs.push_back("-fmath-errno");
+ if (NoMathErrnoWasImpliedByVeclib)
+ D.Diag(clang::diag::warn_drv_math_errno_reenabled_after_veclib)
+ << ArgThatReenabledMathErrnoAfterVeclib->getAsString(Args)
+ << VeclibArg->getAsString(Args);
+ }
if (AssociativeMath && ReciprocalMath && !SignedZeros && ApproxFunc &&
!TrappingMath)
diff --git a/clang/test/Driver/fveclib.c b/clang/test/Driver/fveclib.c
index 797b7b2a03d456..9315de47638fa0 100644
--- a/clang/test/Driver/fveclib.c
+++ b/clang/test/Driver/fveclib.c
@@ -75,10 +75,22 @@
// CHECK-ERRNO-ARMPL: "-fveclib=ArmPL"
// CHECK-ERRNO-ARMPL-NOT: "-fmath-errno"
-// RUN: %clang -### --target=aarch64-linux-gnu -fveclib=ArmPL -fmath-errno %s 2>&1 | FileCheck --check-prefix=CHECK-FORCE-ERRNO-ARMPL %s
-// CHECK-FORCE-ERRNO-ARMPL: "-fveclib=ArmPL"
-// CHECK-FORCE-ERRNO-ARMPL-SAME: "-fmath-errno"
-
-// RUN: %clang -### --target=aarch64-linux-gnu -fveclib=SLEEF -fmath-errno %s 2>&1 | FileCheck --check-prefix=CHECK-FORCE-ERRNO-SLEEF %s
-// CHECK-FORCE-ERRNO-SLEEF: "-fveclib=SLEEF"
-// CHECK-FORCE-ERRNO-SLEEF-SAME: "-fmath-errno"
+// RUN: %clang -### --target=aarch64-linux-gnu -fveclib=ArmPL -fmath-errno %s 2>&1 | FileCheck --check-prefix=CHECK-REENABLE-ERRNO-ARMPL %s
+// CHECK-REENABLE-ERRNO-ARMPL: math errno re-enabled by '-fmath-errno' after it was implicitly disabled by '-fveclib=ArmPL', this may prevent vectorization with the specified vector library
+// CHECK-REENABLE-ERRNO-ARMPL: "-fveclib=ArmPL"
+// CHECK-REENABLE-ERRNO-ARMPL-SAME: "-fmath-errno"
+
+// RUN: %clang -### --target=aarch64-linux-gnu -fveclib=SLEEF -fmath-errno %s 2>&1 | FileCheck --check-prefix=CHECK-REENABLE-ERRNO-SLEEF %s
+// CHECK-REENABLE-ERRNO-SLEEF: math errno re-enabled by '-fmath-errno' after it was implicitly disabled by '-fveclib=SLEEF', this may prevent vectorization with the specified vector library
+// CHECK-REENABLE-ERRNO-SLEEF: "-fveclib=SLEEF"
+// CHECK-REENABLE-ERRNO-SLEEF-SAME: "-fmath-errno"
+
+// RUN: %clang -### --target=aarch64-linux-gnu -fveclib=ArmPL -fno-fast-math %s 2>&1 | FileCheck --check-prefix=CHECK-REENABLE-ERRNO-NFM %s
+// CHECK-REENABLE-ERRNO-NFM: math errno re-enabled by '-fno-fast-math' after it was implicitly disabled by '-fveclib=ArmPL', this may prevent vectorization with the specified vector library
+// CHECK-REENABLE-ERRNO-NFM: "-fveclib=ArmPL"
+// CHECK-REENABLE-ERRNO-NFM-SAME: "-fmath-errno"
+
+// RUN: %clang -### --target=aarch64-linux-gnu -fveclib=ArmPL -ffp-model=strict %s 2>&1 | FileCheck --check-prefix=CHECK-REENABLE-ERRNO-FP-MODEL %s
+// CHECK-REENABLE-ERRNO-FP-MODEL: math errno re-enabled by '-ffp-model=strict' after it was implicitly disabled by '-fveclib=ArmPL', this may prevent vectorization with the specified vector library
+// CHECK-REENABLE-ERRNO-FP-MODEL: "-fveclib=ArmPL"
+// CHECK-REENABLE-ERRNO-FP-MODEL-SAME: "-fmath-errno"
More information about the cfe-commits
mailing list