assert(Reg.isValid() && "Expected valid register!");
while (MachineInstr *MI = getDefIgnoringCopies(Reg, MRI)) {
unsigned Opc = MI->getOpcode();
+
+ if (!MI->getOperand(0).isReg() ||
+ !MRI.hasOneUse(MI->getOperand(0).getReg()))
+ break;
+
// (tbz (any_ext x), b) -> (tbz x, b) if we don't use the extended bits.
//
// (tbz (trunc x), b) -> (tbz x, b) is always safe, because the bit number
}
}
- // Didn't find a constant. Bail out of the loop.
- if (!C)
+ // Didn't find a constant or viable register. Bail out of the loop.
+ if (!C || !TestReg.isValid())
break;
// We found a suitable instruction with a constant. Check to see if we can
}
// Check if we found anything worth folding.
- if (!NextReg.isValid() || !MRI.hasOneUse(NextReg))
- break;
+ if (!NextReg.isValid())
+ return Reg;
Reg = NextReg;
}
; CHECK: %copy:gpr32 = COPY $w0
; CHECK: [[SUBREG_TO_REG:%[0-9]+]]:gpr64 = SUBREG_TO_REG 0, %copy, %subreg.sub_32
; CHECK: %zext:gpr64 = UBFMXri [[SUBREG_TO_REG]], 0, 31
- ; CHECK: TBNZW %copy, 3, %bb.1
+ ; CHECK: [[COPY:%[0-9]+]]:gpr64all = COPY %zext
+ ; CHECK: [[COPY1:%[0-9]+]]:gpr32all = COPY [[COPY]].sub_32
+ ; CHECK: [[COPY2:%[0-9]+]]:gpr32 = COPY [[COPY1]]
+ ; CHECK: TBNZW [[COPY2]], 3, %bb.1
; CHECK: B %bb.0
; CHECK: bb.1:
; CHECK: $x0 = COPY %zext
G_BR %bb.0
bb.1:
RET_ReallyLR
+
+...
+---
+name: dont_fold_shl_3
+alignment: 4
+legalized: true
+regBankSelected: true
+body: |
+ ; CHECK-LABEL: name: dont_fold_shl_3
+ ; CHECK: bb.0:
+ ; CHECK: successors: %bb.0(0x40000000), %bb.1(0x40000000)
+ ; CHECK: %copy:gpr64 = COPY $x0
+ ; CHECK: %shl:gpr64 = UBFMXri %copy, 62, 61
+ ; CHECK: [[COPY:%[0-9]+]]:gpr64all = COPY %shl
+ ; CHECK: [[COPY1:%[0-9]+]]:gpr32all = COPY [[COPY]].sub_32
+ ; CHECK: [[COPY2:%[0-9]+]]:gpr32 = COPY [[COPY1]]
+ ; CHECK: TBNZW [[COPY2]], 3, %bb.1
+ ; CHECK: B %bb.0
+ ; CHECK: bb.1:
+ ; CHECK: %second_use:gpr64sp = ORRXri %shl, 8000
+ ; CHECK: $x0 = COPY %second_use
+ ; CHECK: RET_ReallyLR implicit $x0
+ bb.0:
+ successors: %bb.0, %bb.1
+ liveins: $x0
+ %copy:gpr(s64) = COPY $x0
+ %bit:gpr(s64) = G_CONSTANT i64 8
+ %zero:gpr(s64) = G_CONSTANT i64 0
+ %fold_cst:gpr(s64) = G_CONSTANT i64 2
+
+ ; Don't walk past the G_SHL when it's used more than once.
+ %shl:gpr(s64) = G_SHL %copy, %fold_cst
+ %and:gpr(s64) = G_AND %shl, %bit
+ %cmp:gpr(s32) = G_ICMP intpred(ne), %and(s64), %zero
+ %cmp_trunc:gpr(s1) = G_TRUNC %cmp(s32)
+ G_BRCOND %cmp_trunc(s1), %bb.1
+ G_BR %bb.0
+
+ bb.1:
+ %second_use:gpr(s64) = G_OR %shl, %bit
+ $x0 = COPY %second_use
+ RET_ReallyLR implicit $x0