Re: [PATCH v2][ARM] Disable code hoisting with -O3 (PR80155)

[Wilco Dijkstra]

ping

Hi,

While code hoisting generally improves codesize, it can affect performance
negatively. Benchmarking shows it doesn't help SPEC and negatively affects
embedded benchmarks. Since the impact is relatively small with -O2 and mainly
affects -O3, the simplest option is to disable code hoisting for -O3 and higher.

OK for commit?

ChangeLog:
2019-11-26  Wilco Dijkstra  <wdijk...@arm.com>

        PR tree-optimization/80155
        * common/config/arm/arm-common.c (arm_option_optimization_table):
        Disable -fcode-hoisting with -O3.
--

diff --git a/gcc/common/config/arm/arm-common.c 
b/gcc/common/config/arm/arm-common.c
index 
b761d3abd670a144a593c4b410b1e7fbdcb52f56..3e11f21b7dd76cc071b645c32a6fdb4a92511279
 100644
--- a/gcc/common/config/arm/arm-common.c
+++ b/gcc/common/config/arm/arm-common.c
@@ -39,6 +39,8 @@ static const struct default_options 
arm_option_optimization_table[] =
     /* Enable section anchors by default at -O1 or higher.  */
     { OPT_LEVELS_1_PLUS, OPT_fsection_anchors, NULL, 1 },
     { OPT_LEVELS_FAST, OPT_fsched_pressure, NULL, 1 },
+    /* Disable code hoisting with -O3 or higher.  */
+    { OPT_LEVELS_3_PLUS, OPT_fcode_hoisting, NULL, 0 },
     { OPT_LEVELS_NONE, 0, NULL, 0 }
   };