Patchwork Don't make local variables static in ldbl-96 j1l [committed]

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Submitter Joseph Myers
Date Dec. 6, 2017, 3:20 p.m.
Message ID <alpine.DEB.2.20.1712061519430.17874@digraph.polyomino.org.uk>
Download mbox | patch
Permalink /patch/24760/
State New
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Comments

Joseph Myers - Dec. 6, 2017, 3:20 p.m.
The ldbl-96 implementation of j1l has some function-local variables
that are declared static for no apparent reason (this dates back to
the first addition of that file).

Any vaguely recent compiler, probably including any that are supported
for building glibc, optimizes away the "static" here, as the values of
the variables on entry to the function are dead.  So there is not
actually a user-visible bug here at present (but with any compilers
that didn't optimize away the static at all, possibly building with
less or no optimization, so that the function stored intermediate
values to and then loaded them from the variables, there would have
been a thread-safety issue).  But the "static" clearly doesn't belong
there and might potentially make things unsafe were compilation
without optimization to be supported in future, so this patch removes
it.

Tested for x86_64.  Committed.

2017-12-06  Joseph Myers  <joseph@codesourcery.com>

	* sysdeps/ieee754/ldbl-96/e_j1l.c (qone): Don't make local
	variables static.

Patch

diff --git a/sysdeps/ieee754/ldbl-96/e_j1l.c b/sysdeps/ieee754/ldbl-96/e_j1l.c
index a8a9902..4f07b0b 100644
--- a/sysdeps/ieee754/ldbl-96/e_j1l.c
+++ b/sysdeps/ieee754/ldbl-96/e_j1l.c
@@ -507,7 +507,7 @@  static long double
 qone (long double x)
 {
   const long double *p, *q;
-  static long double s, r, z;
+  long double s, r, z;
   int32_t ix;
   uint32_t se, i0, i1;