If an indvar with a variable stride is used by the exit condition, go ahead
and handle it like constant stride vars. This fixes some bad codegen in
variable stride cases. For example, it compiles this:
void foo(int k, int i) {
for (k=i+i; k <= 8192; k+=i)
flags2[k] = 0;
}
to:
LBB1_1: #bb.preheader
movl %eax, %ecx
addl %ecx, %ecx
movl L_flags2$non_lazy_ptr, %edx
LBB1_2: #bb
movb $0, (%edx,%ecx)
addl %eax, %ecx
cmpl $8192, %ecx
jle LBB1_2 #bb
LBB1_5: #return
ret
or (if the array is local and we are in dynamic-nonpic or static mode):
LBB3_2: #bb
movb $0, _flags2(%ecx)
addl %eax, %ecx
cmpl $8192, %ecx
jle LBB3_2 #bb
and:
lis r2, ha16(L_flags2$non_lazy_ptr)
lwz r2, lo16(L_flags2$non_lazy_ptr)(r2)
slwi r3, r4, 1
LBB1_2: ;bb
li r5, 0
add r6, r4, r3
stbx r5, r2, r3
cmpwi cr0, r6, 8192
bgt cr0, LBB1_5 ;return
instead of:
leal (%eax,%eax,2), %ecx
movl %eax, %edx
addl %edx, %edx
addl L_flags2$non_lazy_ptr, %edx
xorl %esi, %esi
LBB1_2: #bb
movb $0, (%edx,%esi)
movl %eax, %edi
addl %esi, %edi
addl %ecx, %esi
cmpl $8192, %esi
jg LBB1_5 #return
and:
lis r2, ha16(L_flags2$non_lazy_ptr)
lwz r2, lo16(L_flags2$non_lazy_ptr)(r2)
mulli r3, r4, 3
slwi r5, r4, 1
li r6, 0
add r2, r2, r5
LBB1_2: ;bb
li r5, 0
add r7, r3, r6
stbx r5, r2, r6
add r6, r4, r6
cmpwi cr0, r7, 8192
ble cr0, LBB1_2 ;bb
This speeds up Benchmarks/Shootout/sieve from 8.533s to 6.464s and
implements LoopStrengthReduce/var_stride_used_by_compare.ll
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@31809 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed