[libc] add shared divsf3 builtin (#205679)

Re-exposes LLVM-libc's `__divsf3` as `shared::divsf3` for reuse by
compiler-rt's builtins.

Stacked change - merge these first:
- #200094
- #205669
- #205670
- #205671
- #205672
- #205673
- #205674
- #205675
- #205676
- #205677
- #205678

Part of #197824

libc/shared/builtins.h

@@ -21,6 +21,7 @@
 #include "builtins/addsf3.h"
 #include "builtins/addtf3.h"
 #include "builtins/divdf3.h"
+#include "builtins/divsf3.h"
 #include "builtins/divtf3.h"
 #include "builtins/muldf3.h"
 #include "builtins/mulsf3.h"

libc/shared/builtins/divsf3.h

@@ -0,0 +1,29 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// This header exposes LLVM-libc's __divsf3 implementation as shared::divsf3 so
+/// that it can be reused by compiler-rt's builtins.
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIBC_SHARED_BUILTINS_DIVSF3_H
+#define LLVM_LIBC_SHARED_BUILTINS_DIVSF3_H
+
+#include "shared/libc_common.h"
+#include "src/__support/builtins/divsf3.h"
+
+namespace LIBC_NAMESPACE_DECL {
+namespace shared {
+
+using builtins::divsf3;
+
+} // namespace shared
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LLVM_LIBC_SHARED_BUILTINS_DIVSF3_H

libc/src/__support/builtins/CMakeLists.txt

@@ -100,3 +100,12 @@ add_header_library(
     libc.src.__support.FPUtil.generic.mul
     libc.src.__support.macros.config
 )
+
+add_header_library(
+  divsf3
+  HDRS
+    divsf3.h
+  DEPENDS
+    libc.src.__support.FPUtil.generic.div
+    libc.src.__support.macros.config
+)

libc/src/__support/builtins/divsf3.h

@@ -0,0 +1,32 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// This header exposes LLVM-libc's __divsf3 implementation as builtins::divsf3
+/// so that it can be reused by compiler-rt's builtins.
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIBC_SRC___SUPPORT_BUILTINS_DIVSF3_H
+#define LLVM_LIBC_SRC___SUPPORT_BUILTINS_DIVSF3_H
+
+#include "src/__support/FPUtil/generic/div.h"
+#include "src/__support/macros/config.h"
+
+namespace LIBC_NAMESPACE_DECL {
+namespace builtins {
+
+// Division at float precision; mirrors compiler-rt's __divsf3.
+LIBC_INLINE float divsf3(float x, float y) {
+  return fputil::generic::div<float>(x, y);
+}
+
+} // namespace builtins
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LLVM_LIBC_SRC___SUPPORT_BUILTINS_DIVSF3_H

libc/test/shared/CMakeLists.txt

@@ -831,6 +831,7 @@ add_fp_unittest(
     libc.src.__support.builtins.addsf3
     libc.src.__support.builtins.addtf3
     libc.src.__support.builtins.divdf3
+    libc.src.__support.builtins.divsf3
     libc.src.__support.builtins.divtf3
     libc.src.__support.builtins.muldf3
     libc.src.__support.builtins.mulsf3

libc/test/shared/shared_builtins_test.cpp

@@ -12,6 +12,7 @@
 
 TEST(LlvmLibcSharedBuiltinsTest, AllFloat) {
   EXPECT_FP_EQ(3.0f, LIBC_NAMESPACE::shared::addsf3(1.0f, 2.0f));
+  EXPECT_FP_EQ(3.0f, LIBC_NAMESPACE::shared::divsf3(6.0f, 2.0f));
   EXPECT_FP_EQ(6.0f, LIBC_NAMESPACE::shared::mulsf3(2.0f, 3.0f));
   EXPECT_FP_EQ(2.0f, LIBC_NAMESPACE::shared::subsf3(5.0f, 3.0f));
 }