1 files changed, 99 insertions, 0 deletions
diff --git a/libgcc/config/i386/crtfastmath.c b/libgcc/config/i386/crtfastmath.c
new file mode 100644
index 0000000000..4a2d199830
--- /dev/null
+++ b/libgcc/config/i386/crtfastmath.c
@@ -0,0 +1,99 @@
+/*
+ * Copyright (C) 2005-2017 Free Software Foundation, Inc.
+ *
+ * This file is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 3, or (at your option) any
+ * later version.
+ * 
+ * This file is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ * 
+ * Under Section 7 of GPL version 3, you are granted additional
+ * permissions described in the GCC Runtime Library Exception, version
+ * 3.1, as published by the Free Software Foundation.
+ *
+ * You should have received a copy of the GNU General Public License and
+ * a copy of the GCC Runtime Library Exception along with this program;
+ * see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+ * <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef _SOFT_FLOAT
+#define MXCSR_DAZ (1 << 6)	/* Enable denormals are zero mode */
+#define MXCSR_FTZ (1 << 15)	/* Enable flush to zero mode */
+
+#ifndef __x86_64__
+/* All 64-bit targets have SSE and DAZ;
+   only check them explicitly for 32-bit ones. */
+#include "cpuid.h"
+
+__attribute__ ((target("fxsr,sse")))
+static void
+/* The i386 ABI only requires 4-byte stack alignment, so this is necessary
+   to make sure the fxsave struct gets correct alignment.
+   See PR27537 and PR28621.  */
+__attribute__ ((force_align_arg_pointer))
+set_fast_math_sse (unsigned int edx)
+{
+  unsigned int mxcsr;
+  
+  if (edx & bit_FXSAVE)
+    {
+      /* Check if DAZ is available.  */
+      struct
+      {
+	unsigned short cwd;
+	unsigned short swd;
+	unsigned short twd;
+	unsigned short fop;
+	unsigned int fip;
+	unsigned int fcs;
+	unsigned int foo;
+	unsigned int fos;
+	unsigned int mxcsr;
+	unsigned int mxcsr_mask;
+	unsigned int st_space[32];
+	unsigned int xmm_space[32];
+	unsigned int padding[56];
+      } __attribute__ ((aligned (16))) fxsave;
+
+      /* This is necessary since some implementations of FXSAVE
+	 do not modify reserved areas within the image.  */
+      fxsave.mxcsr_mask = 0;
+
+      __builtin_ia32_fxsave (&fxsave);
+
+      mxcsr = fxsave.mxcsr;
+
+      if (fxsave.mxcsr_mask & MXCSR_DAZ)
+	mxcsr |= MXCSR_DAZ;
+    }
+  else
+    mxcsr = __builtin_ia32_stmxcsr ();
+
+  mxcsr |= MXCSR_FTZ;
+  __builtin_ia32_ldmxcsr (mxcsr);
+}
+#endif
+
+static void __attribute__((constructor))
+set_fast_math (void)
+{
+#ifndef __x86_64__
+  unsigned int eax, ebx, ecx, edx;
+
+  if (!__get_cpuid (1, &eax, &ebx, &ecx, &edx))
+    return;
+
+  if (edx & bit_SSE)
+    set_fast_math_sse (edx);
+#else
+  unsigned int mxcsr = __builtin_ia32_stmxcsr ();
+  mxcsr |= MXCSR_DAZ | MXCSR_FTZ;
+  __builtin_ia32_ldmxcsr (mxcsr);
+#endif
+}
+#endif