https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90554
Bug ID: 90554
Summary: Missed vectorization with conditionally defined the
end of the loop
Product: gcc
Version: tree-ssa
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: david.bolvansky at gmail dot com
Target Milestone: ---
int vectorize(int b, unsigned *x, unsigned *y, int N, int NN)
{
int sum = 0;
int end = b ? N : NN;
unsigned *p = b ? x : y;
for(int i = 0; i < end; ++i) {
sum += p[i];
}
return sum;
}
Trunk -O3
vectorize:
test edi, edi
cmovne r8d, ecx
cmovne rdx, rsi
test r8d, r8d
jle .L5
lea eax, [r8-1]
lea rcx, [rdx+4+rax*4]
xor eax, eax
.L4:
add eax, DWORD PTR [rdx]
add rdx, 4
cmp rcx, rdx
jne .L4
ret
.L5:
xor eax, eax
ret
ICC or Clang vectorizes this code.
