[clang] 527ef8c - Reland "[X86] Support `_Float16` on SSE2 and up"
Phoebe Wang via cfe-commits
cfe-commits at lists.llvm.org
Mon Jun 27 23:39:58 PDT 2022
Author: Phoebe Wang
Date: 2022-06-28T14:38:56+08:00
New Revision: 527ef8ca981e88a35758c0e4143be6853ea26dfc
URL: https://github.com/llvm/llvm-project/commit/527ef8ca981e88a35758c0e4143be6853ea26dfc
DIFF: https://github.com/llvm/llvm-project/commit/527ef8ca981e88a35758c0e4143be6853ea26dfc.diff
LOG: Reland "[X86] Support `_Float16` on SSE2 and up"
Enable `COMPILER_RT_HAS_FLOAT16` to solve the lit fail.
This is split from D113107 to address #56204 and https://discourse.llvm.org/t/how-to-build-compiler-rt-for-new-x86-half-float-abi/63366
Reviewed By: zahiraam, rjmccall, bkramer
Differential Revision: https://reviews.llvm.org/D128571
Added:
clang/test/CodeGen/X86/Float16-arithmetic.c
clang/test/CodeGen/X86/Float16-complex.c
Modified:
clang/docs/LanguageExtensions.rst
clang/docs/ReleaseNotes.rst
clang/lib/Basic/Targets/X86.cpp
clang/test/Sema/Float16.c
clang/test/Sema/conversion-target-dep.c
clang/test/SemaCXX/Float16.cpp
compiler-rt/test/builtins/CMakeLists.txt
Removed:
clang/test/CodeGen/X86/avx512fp16-complex.c
################################################################################
diff --git a/clang/docs/LanguageExtensions.rst b/clang/docs/LanguageExtensions.rst
index af697fafd8c41..1bac2aee84bd9 100644
--- a/clang/docs/LanguageExtensions.rst
+++ b/clang/docs/LanguageExtensions.rst
@@ -743,7 +743,13 @@ targets pending ABI standardization:
* 64-bit ARM (AArch64)
* AMDGPU
* SPIR
-* X86 (Only available under feature AVX512-FP16)
+* X86 (see below)
+
+On X86 targets, ``_Float16`` is supported as long as SSE2 is available, which
+includes all 64-bit and all recent 32-bit processors. When the target supports
+AVX512-FP16, ``_Float16`` arithmetic is performed using that native support.
+Otherwise, ``_Float16`` arithmetic is performed by promoting to ``float``,
+performing the operation, and then truncating to ``_Float16``.
``_Float16`` will be supported on more targets as they define ABIs for it.
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 3e29987ad2631..733f10a7e4d1a 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -514,6 +514,9 @@ X86 Support in Clang
- Support ``-mharden-sls=[none|all|return|indirect-jmp]`` for straight-line
speculation hardening.
+- Support for the ``_Float16`` type has been added for all targets with SSE2.
+ When AVX512-FP16 is not available, arithmetic on ``_Float16`` is emulated
+ using ``float``.
DWARF Support in Clang
----------------------
diff --git a/clang/lib/Basic/Targets/X86.cpp b/clang/lib/Basic/Targets/X86.cpp
index b83b3517ddf90..0b3d87837ef6a 100644
--- a/clang/lib/Basic/Targets/X86.cpp
+++ b/clang/lib/Basic/Targets/X86.cpp
@@ -239,7 +239,6 @@ bool X86TargetInfo::handleTargetFeatures(std::vector<std::string> &Features,
HasAVX512ER = true;
} else if (Feature == "+avx512fp16") {
HasAVX512FP16 = true;
- HasFloat16 = true;
} else if (Feature == "+avx512pf") {
HasAVX512PF = true;
} else if (Feature == "+avx512dq") {
@@ -355,6 +354,9 @@ bool X86TargetInfo::handleTargetFeatures(std::vector<std::string> &Features,
.Default(NoSSE);
SSELevel = std::max(SSELevel, Level);
+ // Turn on _float16 for x86 (feature sse2)
+ HasFloat16 = SSELevel >= SSE2;
+
MMX3DNowEnum ThreeDNowLevel = llvm::StringSwitch<MMX3DNowEnum>(Feature)
.Case("+3dnowa", AMD3DNowAthlon)
.Case("+3dnow", AMD3DNow)
diff --git a/clang/test/CodeGen/X86/Float16-arithmetic.c b/clang/test/CodeGen/X86/Float16-arithmetic.c
new file mode 100644
index 0000000000000..726da22a22b08
--- /dev/null
+++ b/clang/test/CodeGen/X86/Float16-arithmetic.c
@@ -0,0 +1,29 @@
+// RUN: %clang_cc1 -triple x86_64-unknown-unknown \
+// RUN: -emit-llvm -o - %s | FileCheck %s --check-prefixes=CHECK
+
+// CHECK-NOT: fpext
+// CHECK-NOT: fptrunc
+
+_Float16 add1(_Float16 a, _Float16 b) {
+ return a + b;
+}
+
+_Float16 add2(_Float16 a, _Float16 b, _Float16 c) {
+ return a + b + c;
+}
+
+_Float16 div(_Float16 a, _Float16 b) {
+ return a / b;
+}
+
+_Float16 mul(_Float16 a, _Float16 b) {
+ return a * b;
+}
+
+_Float16 add_and_mul1(_Float16 a, _Float16 b, _Float16 c, _Float16 d) {
+ return a * b + c * d;
+}
+
+_Float16 add_and_mul2(_Float16 a, _Float16 b, _Float16 c, _Float16 d) {
+ return (a - 6 * b) + c;
+}
diff --git a/clang/test/CodeGen/X86/avx512fp16-complex.c b/clang/test/CodeGen/X86/Float16-complex.c
similarity index 96%
rename from clang/test/CodeGen/X86/avx512fp16-complex.c
rename to clang/test/CodeGen/X86/Float16-complex.c
index 8a6b50eb0056b..ebb290c976e7d 100644
--- a/clang/test/CodeGen/X86/avx512fp16-complex.c
+++ b/clang/test/CodeGen/X86/Float16-complex.c
@@ -1,4 +1,5 @@
// RUN: %clang_cc1 %s -O0 -emit-llvm -triple x86_64-unknown-unknown -target-feature +avx512fp16 -o - | FileCheck %s --check-prefix=X86
+// RUN: %clang_cc1 %s -O0 -emit-llvm -triple x86_64-unknown-unknown -o - | FileCheck %s --check-prefix=X86
_Float16 _Complex add_half_rr(_Float16 a, _Float16 b) {
// X86-LABEL: @add_half_rr(
diff --git a/clang/test/Sema/Float16.c b/clang/test/Sema/Float16.c
index f0b94666f74d7..26c604fed27aa 100644
--- a/clang/test/Sema/Float16.c
+++ b/clang/test/Sema/Float16.c
@@ -1,5 +1,6 @@
-// RUN: %clang_cc1 -fsyntax-only -verify -triple x86_64-linux-pc %s
-// RUN: %clang_cc1 -fsyntax-only -verify -triple x86_64-linux-pc -target-feature +avx512fp16 %s -DHAVE
+// RUN: %clang_cc1 -fsyntax-only -verify -triple i686-linux-pc %s
+// RUN: %clang_cc1 -fsyntax-only -verify -triple i686-linux-pc -target-feature +sse2 %s -DHAVE
+// RUN: %clang_cc1 -fsyntax-only -verify -triple x86_64-linux-pc %s -DHAVE
// RUN: %clang_cc1 -fsyntax-only -verify -triple spir-unknown-unknown %s -DHAVE
// RUN: %clang_cc1 -fsyntax-only -verify -triple armv7a-linux-gnu %s -DHAVE
// RUN: %clang_cc1 -fsyntax-only -verify -triple aarch64-linux-gnu %s -DHAVE
diff --git a/clang/test/Sema/conversion-target-dep.c b/clang/test/Sema/conversion-target-dep.c
index 958a4d8b1f076..1b22cb8209343 100644
--- a/clang/test/Sema/conversion-target-dep.c
+++ b/clang/test/Sema/conversion-target-dep.c
@@ -6,7 +6,7 @@
long double ld;
double d;
-_Float16 f16; // x86-error {{_Float16 is not supported on this target}}
+_Float16 f16;
int main(void) {
ld = d; // x86-warning {{implicit conversion increases floating-point precision: 'double' to 'long double'}}
diff --git a/clang/test/SemaCXX/Float16.cpp b/clang/test/SemaCXX/Float16.cpp
index f27c3839854e1..61b02a50687b9 100644
--- a/clang/test/SemaCXX/Float16.cpp
+++ b/clang/test/SemaCXX/Float16.cpp
@@ -1,4 +1,6 @@
-// RUN: %clang_cc1 -fsyntax-only -verify -triple x86_64-linux-pc %s
+// RUN: %clang_cc1 -fsyntax-only -verify -triple i686-linux-pc %s
+// RUN: %clang_cc1 -fsyntax-only -verify -triple i686-linux-pc -target-feature +sse2 %s -DHAVE
+// RUN: %clang_cc1 -fsyntax-only -verify -triple x86_64-linux-pc %s -DHAVE
// RUN: %clang_cc1 -fsyntax-only -verify -triple spir-unknown-unknown %s -DHAVE
// RUN: %clang_cc1 -fsyntax-only -verify -triple armv7a-linux-gnu %s -DHAVE
// RUN: %clang_cc1 -fsyntax-only -verify -triple aarch64-linux-gnu %s -DHAVE
diff --git a/compiler-rt/test/builtins/CMakeLists.txt b/compiler-rt/test/builtins/CMakeLists.txt
index d56ffc69763b6..23d9bf021cd81 100644
--- a/compiler-rt/test/builtins/CMakeLists.txt
+++ b/compiler-rt/test/builtins/CMakeLists.txt
@@ -44,7 +44,7 @@ foreach(arch ${BUILTIN_TEST_ARCH})
string(REPLACE ";" " " BUILTINS_TEST_TARGET_CFLAGS "${BUILTINS_TEST_TARGET_CFLAGS}")
endif()
- if (${arch} MATCHES "arm|aarch64|arm64" AND COMPILER_RT_HAS_FLOAT16)
+ if (${arch} MATCHES "arm|aarch64|arm64|i?86|x86_64|AMD64" AND COMPILER_RT_HAS_FLOAT16)
list(APPEND BUILTINS_TEST_TARGET_CFLAGS -DCOMPILER_RT_HAS_FLOAT16)
string(REPLACE ";" " " BUILTINS_TEST_TARGET_CFLAGS "${BUILTINS_TEST_TARGET_CFLAGS}")
endif()
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