https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102309
Bug ID: 102309
Summary: thumb2-replicated-constant2.c fails on cortex-m7
Product: gcc
Version: 12.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
Assignee: unassigned at gcc dot gnu.org
Reporter: clyon at gcc dot gnu.org
Target Milestone: ---
I've noticed that gcc.target/arm/thumb2-replicated-constant2.c fails when
targeting cortex-m7.
For instance for the first fonction, for cortex-m4 we generate:
foo1:
add r0, r0, #-33489408
adds r0, r0, #1
bx lr
for cortex-m7, we generate:
foo1:
mov r3, r0
ldr r0, .L3
add r0, r0, r3
bx lr
.L4:
.align 2
.L3:
.word -33489407
This is because arm_cortex_m7_tune has 0 in constant_limit, while the generic
arm_v7m_tune has 1.
This setting has been in place since r5-4680 in 2014, see
https://gcc.gnu.org/pipermail/gcc-patches/2014-November/403718.html
Since it was the result of benchmarking, I guess this is a feature, not a bug?
Is this really faster?
