https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120209
Bug ID: 120209
Summary: [SH] Float constant 1.0 is loaded from constant pool
Product: gcc
Version: 15.1.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
Assignee: unassigned at gcc dot gnu.org
Reporter: paul at crapouillou dot net
Target Milestone: ---
With the following code compiled at -Os:
float sh4_floorf(float x) {
float x2 = (float)(int)x;
if (x < -1.0f)
x2 += -1.0f;
return x2;
}
GCC generates:
_sh4_floorf:
mova .L6,r0
fmov.s @r0+,fr1
ftrc fr5,fpul
fcmp/gt fr5,fr1
bf/s .L5
float fpul,fr0
fldi1 fr1
fsub fr1,fr0
.L5:
rts
nop
.L6:
.long -1082130432
Notice how the 1.0f constant is loaded from .L6 using mova + fmov.s, while it
could be loaded using fldi1 directly.
The compiler also does not seem to understand that fr1 contains -1.0f which it
can add to fr0 directly, and instead it will load 1.0f with fldi1 this time and
substract it to fr0.
