http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57278
Bug ID: 57278
Summary: -fno-if-conversion and -fno-if-conversion2 do not work
as intended
Product: gcc
Version: 4.8.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: shiwen.hu at gmail dot com
Created attachment 30115
--> http://gcc.gnu.org/bugzilla/attachment.cgi?id=30115&action=edit
test code and binaries
I tried to use "-fno-if-conversion -fno-if-conversion2" in GCC 4.8.0 targeting
ARM cortex-a15 to replace predicated instructions with branches. However, the
compiled binaries still contain predicated instructions, disregarding whether
generating Thumb or ARM code. Attached are the source code and the two
binaries. Can someone look into the issue?
Below are the commands I used to compile the binaries:
FLAGS="-mfloat-abi=hard -static -static-libgcc -mcpu=cortex-a15
-mtune=cortex-a15 -mfpu=neon-vfpv4 -O3"
$CC $FLAGS -marm -fno-if-conversion -fno-if-conversion2 test_cond.c test_data.c
-o test_cond.a32.nocond.exe
$CC $FLAGS -mthumb -fno-if-conversion -fno-if-conversion2 test_cond.c
test_data.c -o test_cond.t32.nocond.exe
In another note, the code is not optimal in that two of the three sign
extensions in the main function assembly can be moved outside the main loop.
Thanks,
Shiwen
