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| author | Siddhesh Poyarekar <siddhesh@redhat.com> | 2013-05-17 19:10:33 +0530 |
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| committer | Siddhesh Poyarekar <siddhesh@redhat.com> | 2013-05-17 19:10:33 +0530 |
| commit | 48a18de1e1e7dfeab6d034765caaf732b53cfcb7 (patch) | |
| tree | 1710f87c334a2d5cc79c30f9262212697eb814ef | |
| parent | 13d3b41a36c4f28d171a144f8a9baad3a8835981 (diff) | |
| download | glibc-48a18de1e1e7dfeab6d034765caaf732b53cfcb7.tar.gz glibc-48a18de1e1e7dfeab6d034765caaf732b53cfcb7.tar.xz glibc-48a18de1e1e7dfeab6d034765caaf732b53cfcb7.zip | |
Prevent optimizing out of benchmark function call
Resolves: #15424 The compiler would optimize the benchmark function call out of the loop and call it only once, resulting in blazingly fast times for some benchmarks (notably atan, sin and cos). Mark the inputs as volatile so that the code is forced to read again from the input for each iteration.
| -rw-r--r-- | ChangeLog | 7 | ||||
| -rw-r--r-- | NEWS | 2 | ||||
| -rw-r--r-- | benchtests/bench-modf.c | 2 | ||||
| -rwxr-xr-x | scripts/bench.pl | 2 |
4 files changed, 10 insertions, 3 deletions
diff --git a/ChangeLog b/ChangeLog index 78d4804885..58b87d4bc3 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,10 @@ +2013-05-17 Siddhesh Poyarekar <siddhesh@redhat.com> + + [BZ #15424] + * benchtests/bench-modf.c (struct args): Mark arg0 as + volatile. + * scripts/bench.pl: Mark members of struct args as volatile. + 2013-05-17 Adhemerval Zanella <azanella@linux.vnet.ibm.com> * sysdeps/powerpc/fpu/e_hypot.c (GET_TWO_FLOAT_WORD): Fix test for diff --git a/NEWS b/NEWS index 86c287ff29..57c7ee0a8f 100644 --- a/NEWS +++ b/NEWS @@ -17,7 +17,7 @@ Version 2.18 15086, 15160, 15214, 15221, 15232, 15234, 15283, 15285, 15287, 15304, 15305, 15307, 15309, 15327, 15330, 15335, 15336, 15337, 15342, 15346, 15359, 15361, 15366, 15380, 15394, 15395, 15405, 15406, 15409, 15416, - 15418, 15419, 15423, 15426, 15429, 15442, 15448. + 15418, 15419, 15423, 15424, 15426, 15429, 15442, 15448. * CVE-2013-0242 Buffer overrun in regexp matcher has been fixed (Bugzilla #15078). diff --git a/benchtests/bench-modf.c b/benchtests/bench-modf.c index 7fae7dc6ac..2b50665b7e 100644 --- a/benchtests/bench-modf.c +++ b/benchtests/bench-modf.c @@ -21,7 +21,7 @@ extern double modf (double, double *); struct args { - double arg0; + volatile double arg0; } in[] = { { 42.42 }, diff --git a/scripts/bench.pl b/scripts/bench.pl index dcc5ead727..dcf1355282 100755 --- a/scripts/bench.pl +++ b/scripts/bench.pl @@ -71,7 +71,7 @@ else { $decl = "$decl,"; } - $arg_struct = "$arg_struct $arg arg$num;"; + $arg_struct = "$arg_struct volatile $arg arg$num;"; $bench_func = "$bench_func variants[v].in[i].arg$num"; $decl = "$decl $arg"; $num = $num + 1; |