soft-fp: Add _FP_UNREACHABLE.

This patch makes soft-fp use a new macro _FP_UNREACHABLE in place of
calling abort in unreachable default cases of switch statements.
_FP_UNREACHABLE expands to call __builtin_unreachable for GCC 4.5 and
later; the fallback to abort is thus only for kernel use.

Tested for powerpc-nofpu that installed stripped shared libraries are
unchanged by this patch.  Also tested with the math/ tests for mips64
(in the case of fma there *was* previously an abort call generated,
unlike for the other operations - one switch only deals with a subset
of classes for one operand based on what could have been generated in
the earlier part of fma, whereas the other switches deal with all
combinations of two classes - and this is apparently too complicated
for the default case to have been optimized away).

	* soft-fp/soft-fp.h (_FP_UNREACHABLE): New macro.
	* soft-fp/op-common.h (_FP_MUL): Use _FP_UNREACHABLE instead of
	abort.
	(_FP_FMA): Likewise.
	(_FP_DIV): Likewise.

1 files changed, 8 insertions, 0 deletions

diff --git a/ChangeLog b/ChangeLog
index da5c0ef24e..cea5b0e310 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,11 @@
+2015-03-11  Joseph Myers  <joseph@codesourcery.com>
+
+	* soft-fp/soft-fp.h (_FP_UNREACHABLE): New macro.
+	* soft-fp/op-common.h (_FP_MUL): Use _FP_UNREACHABLE instead of
+	abort.
+	(_FP_FMA): Likewise.
+	(_FP_DIV): Likewise.
+
 2015-03-10  Roland McGrath  <roland@hack.frob.com>
 
 	* scripts/evaluate-test.sh: Grok exit code 77 as UNSUPPORTED and exit