https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96682
Bug ID: 96682
Summary: Arm: Wrong code generated for MVE with -O1 and above
optimization options.
Product: gcc
Version: 10.2.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: sripar01 at gcc dot gnu.org
Target Milestone: ---
Target: arm
Created attachment 49074
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=49074&action=edit
test case
$ arm-none-eabi -v
Using built-in specs.
COLLECT_GCC=../MVE_PUBLIC/gcc-arm-none-eabi-10-2020-q2-preview/bin/arm-none-eabi-gcc
COLLECT_LTO_WRAPPER=/media/sripar01/2tb_work/MVE_PUBLIC/gcc-arm-none-eabi-10-2020-q2-preview/bin/../lib/gcc/arm-none-eabi/10.1.1/lto-wrapper
Target: arm-none-eabi
Configured with:
/mnt/workspace/workspace/GCC-10-pipeline/jenkins-GCC-10-pipeline-13_20200625_1593044217/src/gcc/configure
--target=arm-none-eabi
--prefix=/mnt/workspace/workspace/GCC-10-pipeline/jenkins-GCC-10-pipeline-13_20200625_1593044217/install-native
--libexecdir=/mnt/workspace/workspace/GCC-10-pipeline/jenkins-GCC-10-pipeline-13_20200625_1593044217/install-native/lib
--infodir=/mnt/workspace/workspace/GCC-10-pipeline/jenkins-GCC-10-pipeline-13_20200625_1593044217/install-native/share/doc/gcc-arm-none-eabi/info
--mandir=/mnt/workspace/workspace/GCC-10-pipeline/jenkins-GCC-10-pipeline-13_20200625_1593044217/install-native/share/doc/gcc-arm-none-eabi/man
--htmldir=/mnt/workspace/workspace/GCC-10-pipeline/jenkins-GCC-10-pipeline-13_20200625_1593044217/install-native/share/doc/gcc-arm-none-eabi/html
--pdfdir=/mnt/workspace/workspace/GCC-10-pipeline/jenkins-GCC-10-pipeline-13_20200625_1593044217/install-native/share/doc/gcc-arm-none-eabi/pdf
--enable-languages=c,c++ --enable-plugins --disable-decimal-float
--disable-libffi --disable-libgomp --disable-libmudflap --disable-libquadmath
--disable-libssp --disable-libstdcxx-pch --disable-nls --disable-shared
--disable-threads --disable-tls --with-gnu-as --with-gnu-ld --with-newlib
--with-headers=yes --with-python-dir=share/gcc-arm-none-eabi
--with-sysroot=/mnt/workspace/workspace/GCC-10-pipeline/jenkins-GCC-10-pipeline-13_20200625_1593044217/install-native/arm-none-eabi
--build=x86_64-linux-gnu --host=x86_64-linux-gnu
--with-gmp=/mnt/workspace/workspace/GCC-10-pipeline/jenkins-GCC-10-pipeline-13_20200625_1593044217/build-native/host-libs/usr
--with-mpfr=/mnt/workspace/workspace/GCC-10-pipeline/jenkins-GCC-10-pipeline-13_20200625_1593044217/build-native/host-libs/usr
--with-mpc=/mnt/workspace/workspace/GCC-10-pipeline/jenkins-GCC-10-pipeline-13_20200625_1593044217/build-native/host-libs/usr
--with-isl=/mnt/workspace/workspace/GCC-10-pipeline/jenkins-GCC-10-pipeline-13_20200625_1593044217/build-native/host-libs/usr
--with-libelf=/mnt/workspace/workspace/GCC-10-pipeline/jenkins-GCC-10-pipeline-13_20200625_1593044217/build-native/host-libs/usr
--with-host-libstdcxx='-static-libgcc -Wl,-Bstatic,-lstdc++,-Bdynamic -lm'
--with-pkgversion='GNU Arm Embedded Toolchain 10-2020-q2-preview'
--with-multilib-list=rmprofile,aprofile
Thread model: single
Supported LTO compression algorithms: zlib
gcc version 10.1.1 20200529 (release) (GNU Arm Embedded Toolchain
10-2020-q2-preview)
$ arm-none-eabi-gcc bug.c -mfloat-abi=hard -march=armv8.1-m.main+mve.fp -O3 -c
x.i:65:1: warning: return type defaults to 'int' [-Wimplicit-int]
65 | fn1(__fp16 *pSrc) {
| ^~~
/tmp/ccOTL3zZ.s: Assembler messages:
/tmp/ccOTL3zZ.s:40: Error: instruction does not support writeback -- `vldr.16
s15,[r0]!'
vldr.16 and vstr.16 does not support write back for MVE, wrong code-gen for the
attached test case bug.c.
