looks like is happening:
Without the peephole optimizer:
(1) sub r6, r6, #32
orr r12, r12, lr, lsl r9
orr r2, r2, r3, lsl r10
(x) cmp r6, #0
ldr r9, LCPI2_10
ldr r10, LCPI2_11
(2) sub r8, r8, #32
(a) movge r12, lr, lsr r6
(y) cmp r8, #0
LPC2_10:
ldr lr, [pc, r10]
(b) movge r2, r3, lsr r8
With the peephole optimizer:
ldr r9, LCPI2_10
ldr r10, LCPI2_11
(1*) subs r6, r6, #32
(2*) subs r8, r8, #32
(a*) movge r12, lr, lsr r6
(b*) movge r2, r3, lsr r8
(1) is used by (x) for the conditional move at (a). (2) is used by (y) for the
conditional move at (b). After the peephole optimizer, these the flags resulting
from (1*) are ignored and only the flags from (2*) are considered for both
conditional moves.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@117876
91177308-0d34-0410-b5e6-
96231b3b80d8
if (MI->getDesc().isCompare() &&
!MI->getDesc().hasUnmodeledSideEffects()) {
+#if 0
if (OptimizeCmpInstr(MI, MBB, MII))
Changed = true;
else
+#endif
++MII;
} else {
Changed |= OptimizeExtInstr(MI, MBB, LocalMIs);