https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120034
Bug ID: 120034
Summary: Fails to recognize bzhi consistently
Product: gcc
Version: 15.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
Assignee: unassigned at gcc dot gnu.org
Reporter: rguenth at gcc dot gnu.org
Target Milestone: ---
The following testcases manage to emit bzhi only for the first case, not the
others:
#define uint64_t unsigned long
#define uint32_t unsigned int
uint64_t bzhi_emulation(uint64_t value, uint32_t index) {
if (index >= 64) {
return value; // No change if index is out of range
}
uint64_t mask = (1ULL << index) - 1;
return value & mask;
}
uint32_t bzhi_emulation1(uint32_t value, uint32_t index) {
return value & ((1ULL << index) - 1);
}
void foo(uint32_t value1, uint32_t value2);
void bzhi_emulation2(uint32_t value1, uint32_t index, const unsigned char*
const a, const unsigned char* const b) {
uint32_t value;
const uint32_t btMask = (1 << index) - 1;
const uint32_t check = (unsigned int) (a-b);
value = 2*(check&btMask);
value1 = 2*(value1&btMask);
foo(value1, value);
}
uint32_t bzhi_emulation3(uint32_t value1, uint32_t value2, uint32_t index ) {
uint32_t lvalue1;
uint32_t lvalue2;
const uint32_t btMask = (1 << index) - 1;
lvalue1 = 2*(value1&btMask);
lvalue2 = 2*(value2&btMask);
return lvalue1 + lvalue2;
}
void bzhi_emulation4(uint32_t value1, uint32_t value2, uint32_t index ) {
uint32_t lvalue1;
uint32_t lvalue2;
const uint32_t btMask = (1 << index) - 1;
lvalue1 = (value1&btMask);
lvalue2 = (value2&btMask);
foo(lvalue1 , lvalue2);
}
