diff options
Diffstat (limited to 'lib/Target/ARM/ARMAddressingModes.h')
| -rw-r--r-- | lib/Target/ARM/ARMAddressingModes.h | 21 |
1 files changed, 6 insertions, 15 deletions
diff --git a/lib/Target/ARM/ARMAddressingModes.h b/lib/Target/ARM/ARMAddressingModes.h index ea62c3330e643..e68354a42f8da 100644 --- a/lib/Target/ARM/ARMAddressingModes.h +++ b/lib/Target/ARM/ARMAddressingModes.h @@ -151,22 +151,13 @@ namespace ARM_AM { if ((rotr32(Imm, RotAmt) & ~255U) == 0) return (32-RotAmt)&31; // HW rotates right, not left. - // For values like 0xF000000F, we should skip the first run of ones, then + // For values like 0xF000000F, we should ignore the low 6 bits, then // retry the hunt. - if (Imm & 1) { - unsigned TrailingOnes = CountTrailingZeros_32(~Imm); - if (TrailingOnes != 32) { // Avoid overflow on 0xFFFFFFFF - // Restart the search for a high-order bit after the initial seconds of - // ones. - unsigned TZ2 = CountTrailingZeros_32(Imm & ~((1 << TrailingOnes)-1)); - - // Rotate amount must be even. - unsigned RotAmt2 = TZ2 & ~1; - - // If this fits, use it. - if (RotAmt2 != 32 && (rotr32(Imm, RotAmt2) & ~255U) == 0) - return (32-RotAmt2)&31; // HW rotates right, not left. - } + if (Imm & 63U) { + unsigned TZ2 = CountTrailingZeros_32(Imm & ~63U); + unsigned RotAmt2 = TZ2 & ~1; + if ((rotr32(Imm, RotAmt2) & ~255U) == 0) + return (32-RotAmt2)&31; // HW rotates right, not left. } // Otherwise, we have no way to cover this span of bits with a single |