https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98673
--- Comment #5 from jojo <rjiejie at me dot com> ---
Sorry for late :)
Please test with following c case:
long
YTableLookup (long xValue, long xEntries, const long *xAxis,
const long *yTable )
{
int i ;
long xDelta ;
long outValue ;
for (i=0; i<(xEntries - 1); i++)
{
if ((xValue < xAxis[i + 1]) && (xValue >= xAxis[i]))
break ;
}
if (i == (xEntries - 1))
xValue = xAxis[i] ;
xDelta = (long) ((xValue - xAxis[i]) * 1000) / (xAxis[i + 1] - xAxis[i]);
outValue = (long) ((((1000 - xDelta) * (long) yTable[i]) / 1000) +
((xDelta * (long) yTable[i+1]) / 1000)) ;
return outValue ;
}
risc-v cc1 option: -O2 -march=rv32gc -mabi=ilp32d
=================================================
YTableLookup:
addi a1,a1,-1
ble a1,zero,.L2
li a7,4
li a4,0
sub a7,a7,a2
j .L5
.L6:
mv a4,a5
.L5:
lw a6,4(a2)
addi a5,a4,1
add t1,a7,a2
ble a6,a0,.L3
lw t3,0(a2)
slli t4,a4,2
ble t3,a0,.L9
.L3:
addi a2,a2,4
bne a1,a5,.L6
addi a4,a4,2
slli t1,a4,2
addi t4,t1,-4
add t4,a3,t4
li a1,0
li a5,1000
.L4:
or x86 cc1 option: -O2 -march=i386
==================================
YTableLookup:
.LFB0:
pushl %ebp
.LCFI0:
pushl %edi
.LCFI1:
pushl %esi
.LCFI2:
pushl %ebx
.LCFI3:
pushl %ecx
.LCFI4:
movl 24(%esp), %esi
movl 32(%esp), %edi
movl 28(%esp), %eax
decl %eax
testl %eax, %eax
jle .L2
movl $4, %ecx
xorl %edx, %edx
jmp .L5
.align 4
.L6:
movl %ebx, %edx
.L5:
movl (%edi,%ecx), %ebx
cmpl %esi, %ebx
jle .L3
leal -4(%ecx), %ebp
movl %ebp, (%esp)
movl (%edi,%edx,4), %ebp
cmpl %esi, %ebp
jle .L10
.L3:
leal 1(%edx), %ebx
addl $4, %ecx
cmpl %ebx, %eax
jne .L6
leal 8(,%edx,4), %ecx
movl 36(%esp), %eax
leal -4(%eax,%ecx), %esi
xorl %eax, %eax
movl $1000, %ebx
.L4:
Please check the redundancy instruction 'mov' at .L6:
