# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py # # Check that we can fold (x & mask) -> x when (x & mask) is known to equal x. # # RUN: llc -mtriple aarch64 -run-pass=aarch64-postlegalizer-combiner -verify-machineinstrs %s -o - | FileCheck %s --- name: remove_and_with_one_bit legalized: true tracksRegLiveness: true body: | bb.0: liveins: $w0, $w1 ; G_ICMP produces a single bit. The mask is 1. ; ; cmp = 000...0? ; mask = 000...01 ; cmp & mask = 000...0? ; ; Remove the G_AND. ; ; CHECK-LABEL: name: remove_and_with_one_bit ; CHECK: liveins: $w0, $w1 ; CHECK: %x:_(s32) = COPY $w0 ; CHECK: %y:_(s32) = COPY $w1 ; CHECK: %cmp:_(s32) = G_ICMP intpred(eq), %x(s32), %y ; CHECK: $w0 = COPY %cmp(s32) ; CHECK: RET_ReallyLR implicit $w0 %x:_(s32) = COPY $w0 %y:_(s32) = COPY $w1 %cmp:_(s32) = G_ICMP intpred(eq), %x(s32), %y %mask:_(s32) = G_CONSTANT i32 1 %and:_(s32) = G_AND %cmp(s32), %mask $w0 = COPY %and(s32) RET_ReallyLR implicit $w0 ... --- name: remove_and_all_ones_mask legalized: true tracksRegLiveness: true body: | bb.0: liveins: $w0, $w1, $w2 ; -1 is all ones. Therefore z & -1 = z. Remove the G_AND. ; ; CHECK-LABEL: name: remove_and_all_ones_mask ; CHECK: liveins: $w0, $w1, $w2 ; CHECK: %z:_(s32) = COPY $w2 ; CHECK: $w0 = COPY %z(s32) ; CHECK: RET_ReallyLR implicit $w0 %x:_(s32) = COPY $w0 %y:_(s32) = COPY $w1 %z:_(s32) = COPY $w2 %mask:_(s32) = G_CONSTANT i32 -1 %and:_(s32) = G_AND %z(s32), %mask $w0 = COPY %and(s32) RET_ReallyLR implicit $w0 ... --- name: remove_and_all_ones_zext legalized: true tracksRegLiveness: true body: | bb.0: liveins: $w0, $w1, $w2 ; %z is a s32, so it can be at most the all-ones value on 32 bits. ; In decimal this is 4294967295. Any zero-extension of %z is at most this ; value. ; ; Therefore, zext(z) & 4294967295 == z. Remove the G_AND. ; ; CHECK-LABEL: name: remove_and_all_ones_zext ; CHECK: liveins: $w0, $w1, $w2 ; CHECK: %z:_(s32) = COPY $w2 ; CHECK: %ext:_(s64) = G_ZEXT %z(s32) ; CHECK: $x0 = COPY %ext(s64) ; CHECK: RET_ReallyLR implicit $x0 %x:_(s32) = COPY $w0 %y:_(s32) = COPY $w1 %z:_(s32) = COPY $w2 %ext:_(s64) = G_ZEXT %z %mask:_(s64) = G_CONSTANT i64 4294967295 %and:_(s64) = G_AND %ext(s64), %mask $x0 = COPY %and(s64) RET_ReallyLR implicit $x0 ... --- name: remove_and_all_ones_anyext legalized: true tracksRegLiveness: true body: | bb.0: liveins: $w0, $w1, $w2 ; This is the same as the zext case. ; ; CHECK-LABEL: name: remove_and_all_ones_anyext ; CHECK: liveins: $w0, $w1, $w2 ; CHECK: %z:_(s32) = COPY $w2 ; CHECK: %ext:_(s64) = G_ZEXT %z(s32) ; CHECK: $x0 = COPY %ext(s64) ; CHECK: RET_ReallyLR implicit $x0 %x:_(s32) = COPY $w0 %y:_(s32) = COPY $w1 %z:_(s32) = COPY $w2 %ext:_(s64) = G_ZEXT %z %mask:_(s64) = G_CONSTANT i64 4294967295 %and:_(s64) = G_AND %ext(s64), %mask $x0 = COPY %and(s64) RET_ReallyLR implicit $x0 ... --- name: dont_remove_all_ones_sext legalized: true tracksRegLiveness: true body: | bb.0: liveins: $w0, $w1, $w2 ; We don't know if the sign bit is set on %z. So, the value in %ext may have ; higher bits set than 4294967295. ; ; CHECK-LABEL: name: dont_remove_all_ones_sext ; CHECK: liveins: $w0, $w1, $w2 ; CHECK: %z:_(s32) = COPY $w2 ; CHECK: %ext:_(s64) = G_SEXT %z(s32) ; CHECK: %mask:_(s64) = G_CONSTANT i64 4294967295 ; CHECK: %and:_(s64) = G_AND %ext, %mask ; CHECK: $x0 = COPY %and(s64) ; CHECK: RET_ReallyLR implicit $x0 %x:_(s32) = COPY $w0 %y:_(s32) = COPY $w1 %z:_(s32) = COPY $w2 %ext:_(s64) = G_SEXT %z %mask:_(s64) = G_CONSTANT i64 4294967295 %and:_(s64) = G_AND %ext(s64), %mask $x0 = COPY %and(s64) RET_ReallyLR implicit $x0 ... --- name: remove_and_positive_constant_sext legalized: true tracksRegLiveness: true body: | bb.0: liveins: $w0, $w1, $w2 ; We know the sign bit is not set on %z. Therefore, ; ; z = ext = 42 = 000...0101010 ; mask = 0000...0111111 ; ; So z & mask == z ; CHECK-LABEL: name: remove_and_positive_constant_sext ; CHECK: liveins: $w0, $w1, $w2 ; CHECK: %z:_(s32) = G_CONSTANT i32 42 ; CHECK: %ext:_(s64) = G_SEXT %z(s32) ; CHECK: $x0 = COPY %ext(s64) ; CHECK: RET_ReallyLR implicit $x0 %x:_(s32) = COPY $w0 %y:_(s32) = COPY $w1 %z:_(s32) = G_CONSTANT i32 42 %ext:_(s64) = G_SEXT %z %mask:_(s64) = G_CONSTANT i64 63 %and:_(s64) = G_AND %ext(s64), %mask $x0 = COPY %and(s64) RET_ReallyLR implicit $x0 ... --- name: not_a_mask legalized: true tracksRegLiveness: true body: | bb.0: liveins: $w0, $w1 ; 6 is not a mask, so we should still have the G_AND. ; ; CHECK-LABEL: name: not_a_mask ; CHECK: liveins: $w0, $w1 ; CHECK: %x:_(s32) = COPY $w0 ; CHECK: %y:_(s32) = COPY $w1 ; CHECK: %cmp:_(s32) = G_ICMP intpred(eq), %x(s32), %y ; CHECK: %mask:_(s32) = G_CONSTANT i32 6 ; CHECK: %and:_(s32) = G_AND %cmp, %mask ; CHECK: $w0 = COPY %and(s32) ; CHECK: RET_ReallyLR implicit $w0 %x:_(s32) = COPY $w0 %y:_(s32) = COPY $w1 %cmp:_(s32) = G_ICMP intpred(eq), %x(s32), %y %mask:_(s32) = G_CONSTANT i32 6 %and:_(s32) = G_AND %cmp(s32), %mask $w0 = COPY %and(s32) RET_ReallyLR implicit $w0 ... --- name: unknown_val legalized: true tracksRegLiveness: true body: | bb.0: liveins: $w0, $w1, $w2 ; We don't know what's in $w2, so we can't remove the G_AND without a mask ; that fills every bit in the type. ; ; CHECK-LABEL: name: unknown_val ; CHECK: liveins: $w0, $w1, $w2 ; CHECK: %z:_(s32) = COPY $w2 ; CHECK: %one:_(s32) = G_CONSTANT i32 32 ; CHECK: %and:_(s32) = G_AND %z, %one ; CHECK: $w0 = COPY %and(s32) ; CHECK: RET_ReallyLR implicit $w0 %x:_(s32) = COPY $w0 %y:_(s32) = COPY $w1 %z:_(s32) = COPY $w2 %one:_(s32) = G_CONSTANT i32 32 %and:_(s32) = G_AND %z(s32), %one $w0 = COPY %and(s32) RET_ReallyLR implicit $w0 ...