http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49911
Summary: vrp2 + -fstrict-enums incorrectly remove predicate
Product: gcc
Version: 4.7.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
AssignedTo: unassig...@gcc.gnu.org
ReportedBy: rafael.espind...@gmail.com
with a r176947 cc1plus, running
cc1plus -fstrict-enums -fdump-tree-all ~/tmpfs/test2.ii -fno-rtti
-fno-exceptions -fno-strict-aliasing -m32 -O2
in
extern void JS_Assert();
typedef enum {
eax, ecx, edx, ebx, esp, ebp,
esi, edi }
RegisterID;
union StateRemat {
RegisterID reg_;
int offset_;
};
static StateRemat FromRegister(RegisterID reg) {
StateRemat sr;
sr.reg_ = reg;
return sr;
}
static StateRemat FromAddress3(int address) {
StateRemat sr;
sr.offset_ = address;
//sr.offset_ = 0;
if (address < 46 && address >= 0) {
JS_Assert();
}
return sr;
}
struct FrameState {
StateRemat dataRematInfo2(bool y, int z) {
if (y) return FromRegister(RegisterID(1));
return FromAddress3(z);
}
};
FrameState frame;
StateRemat x;
void jsop_setelem(bool y, int z) {
x = frame.dataRematInfo2(y, z);
}
produces a test2.ii.123t.vrp2 with:
Folding predicate SR.6_11 <= 45 to 1
replacing the "sr.offset_ = address" line with sr.offset_ = 0 prevents the
transformation.
