http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49526
Summary: ARM missed optimization: SMMUL instruction
Product: gcc
Version: 4.7.0
Status: UNCONFIRMED
Severity: enhancement
Priority: P3
Component: target
AssignedTo: unassig...@gcc.gnu.org
ReportedBy: siarhei.siamas...@gmail.com
$ cat test.c
int smmul(int a, int b) { return ((long long)a * b) >> 32; }
$ arm-none-linux-gnueabi-gcc -O2 -S -mcpu=cortex-a8 test.c
$ cat test.s
.cpu cortex-a8
.fpu softvfp
.eabi_attribute 20, 1
.eabi_attribute 21, 1
.eabi_attribute 23, 3
.eabi_attribute 24, 1
.eabi_attribute 25, 1
.eabi_attribute 26, 2
.eabi_attribute 30, 2
.eabi_attribute 18, 4
.file "test.c"
.text
.align 2
.global smmul
.type smmul, %function
smmul:
@ args = 0, pretend = 0, frame = 0
@ frame_needed = 0, uses_anonymous_args = 0
@ link register save eliminated.
smull r0, r1, r0, r1
mov r0, r1
bx lr
.size smmul, .-smmul
.ident "GCC: (GNU) 4.7.0 20110624 (experimental)"
.section .note.GNU-stack,"",%progbits
