https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92455
--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
You need partial-PRE to perform the desired transform. With -O3 or -O2
-ftree-partial-pre we do what you suggest (plus also cache *max->ptr in
exchange
for another IV):
f1:
.LFB0:
.cfi_startproc
movq (%rdi), %rax
leaq 40(%rdi), %rcx
movq %rdi, %rsi
movl (%rax), %edx
.L3:
movq 8(%rdi), %rax
addq $8, %rdi
movl (%rax), %eax
cmpl %edx, %eax
jle .L2
movl %eax, %edx
movq %rdi, %rsi
.L2:
cmpq %rdi, %rcx
jne .L3
movq (%rsi), %rax
ret
because of the two conditional values (*max and *max->ptr_) the cmov
transform doesn't trigger.
