From: Joseph Myers <joseph@codesourcery.com>
Date: Wed, 11 Mar 2015 01:14:15 +0000 (+0000)
Subject: soft-fp: Add _FP_UNREACHABLE.
X-Git-Tag: glibc-2.22~484
X-Git-Url: https://sourceware.org/git/?a=commitdiff_plain;h=068a6274556f9f362443648f4fd47525c8cf2dba;p=glibc.git

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.
---

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
diff --git a/soft-fp/op-common.h b/soft-fp/op-common.h
index 0a2f86aad9..83c2156954 100644
--- a/soft-fp/op-common.h
+++ b/soft-fp/op-common.h
@@ -927,7 +927,7 @@
 	  break;						\
 								\
 	default:						\
-	  abort ();						\
+	  _FP_UNREACHABLE;					\
 	}							\
     }								\
   while (0)
@@ -1092,7 +1092,7 @@
 	  break;							\
 									\
 	default:							\
-	  abort ();							\
+	  _FP_UNREACHABLE;						\
 	}								\
 									\
       /* T = X * Y is zero, infinity or NaN.  */			\
@@ -1148,7 +1148,7 @@
 	  break;							\
 									\
 	default:							\
-	  abort ();							\
+	  _FP_UNREACHABLE;						\
 	}								\
     done_fma: ;								\
     }									\
@@ -1215,7 +1215,7 @@
 	  break;						\
 								\
 	default:						\
-	  abort ();						\
+	  _FP_UNREACHABLE;					\
 	}							\
     }								\
   while (0)
diff --git a/soft-fp/soft-fp.h b/soft-fp/soft-fp.h
index bb68df9160..b247125a39 100644
--- a/soft-fp/soft-fp.h
+++ b/soft-fp/soft-fp.h
@@ -51,6 +51,15 @@
 # endif
 #endif
 
+/* For unreachable default cases in switch statements over bitwise OR
+   of FP_CLS_* values.  */
+#if (defined __GNUC__							\
+     && (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 5)))
+# define _FP_UNREACHABLE	__builtin_unreachable ()
+#else
+# define _FP_UNREACHABLE	abort ()
+#endif
+
 /* In the Linux kernel, some architectures have a single function that
    uses different kinds of unpacking and packing depending on the
    instruction being emulated, meaning it is not readily visible to