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[X86] Remove brand_id check from cpu_indicator_init. 

Brand index was a feature some Pentium III and Pentium 4 CPUs.
It provided an index into a software lookup table to provide a
brand name for the CPU. This is separate from the family/model.

It's unclear to me why this index being non-zero was used to
block checking family/model. None of the CPUs that had a non-zero
brand index are supported by __builtin_cpu_is or target
multi-versioning so this should have no real effect.
This commit is contained in:
Craig Topper 2020-06-12 20:35:47 -07:00
parent 339e49e2ca
commit 033bf61cc5
1 changed files with 2 additions and 6 deletions
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8
compiler-rt/lib/builtins/cpu_model.c
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@ -270,14 +270,11 @@ static void detectX86FamilyModel(unsigned EAX, unsigned *Family,
}
static void getIntelProcessorTypeAndSubtype(unsigned Family, unsigned Model,
unsigned Brand_id,
const unsigned *Features,
unsigned *Type, unsigned *Subtype) {
#define testFeature(F) \
(Features[F / 32] & (F % 32)) != 0
if (Brand_id != 0)
return;
switch (Family) {
case 6:
switch (Model) {
@ -651,7 +648,7 @@ int CONSTRUCTOR_ATTRIBUTE __cpu_indicator_init(void) {
unsigned EAX, EBX, ECX, EDX;
unsigned MaxLeaf = 5;
unsigned Vendor;
unsigned Model, Family, Brand_id;
unsigned Model, Family;
unsigned Features[2];
// This function needs to run just once.
@ -668,7 +665,6 @@ int CONSTRUCTOR_ATTRIBUTE __cpu_indicator_init(void) {
}
getX86CpuIDAndInfo(1, &EAX, &EBX, &ECX, &EDX);
detectX86FamilyModel(EAX, &Family, &Model);
Brand_id = EBX & 0xff;
// Find available features.
getAvailableFeatures(ECX, EDX, MaxLeaf, &Features[0]);
@ -677,7 +673,7 @@ int CONSTRUCTOR_ATTRIBUTE __cpu_indicator_init(void) {
if (Vendor == SIG_INTEL) {
// Get CPU type.
getIntelProcessorTypeAndSubtype(Family, Model, Brand_id, &Features[0],
getIntelProcessorTypeAndSubtype(Family, Model, &Features[0],
&(__cpu_model.__cpu_type),
&(__cpu_model.__cpu_subtype));
__cpu_model.__cpu_vendor = VENDOR_INTEL;