; NOTE: Assertions have been autogenerated by utils/update_test_checks.py ; RUN: opt < %s -instcombine -S | FileCheck %s ; Given pattern: ; icmp eq/ne (and ((x shift Q), (y oppositeshift K))), 0 ; we should move shifts to the same hand of 'and', i.e. e.g. rewrite as ; icmp eq/ne (and (((x shift Q) shift K), y)), 0 ; We are only interested in opposite logical shifts here. ; We still can handle the case where there is a truncation between a shift ; and an 'and', thought the legality check isn't obvious. ;------------------------------------------------------------------------------- ; Basic scalar tests ;------------------------------------------------------------------------------- ; This fold can't be performed for fully variable %x and %y define i1 @n0(i32 %x, i64 %y, i32 %len) { ; CHECK-LABEL: @n0( ; CHECK-NEXT: [[T0:%.*]] = sub i32 32, [[LEN:%.*]] ; CHECK-NEXT: [[T1:%.*]] = shl i32 [[X:%.*]], [[T0]] ; CHECK-NEXT: [[T2:%.*]] = add i32 [[LEN]], -16 ; CHECK-NEXT: [[T2_WIDE:%.*]] = zext i32 [[T2]] to i64 ; CHECK-NEXT: [[T3:%.*]] = lshr i64 [[Y:%.*]], [[T2_WIDE]] ; CHECK-NEXT: [[T3_TRUNC:%.*]] = trunc i64 [[T3]] to i32 ; CHECK-NEXT: [[T4:%.*]] = and i32 [[T1]], [[T3_TRUNC]] ; CHECK-NEXT: [[T5:%.*]] = icmp ne i32 [[T4]], 0 ; CHECK-NEXT: ret i1 [[T5]] ; %t0 = sub i32 32, %len %t1 = shl i32 %x, %t0 %t2 = add i32 %len, -16 %t2_wide = zext i32 %t2 to i64 %t3 = lshr i64 %y, %t2_wide %t3_trunc = trunc i64 %t3 to i32 %t4 = and i32 %t1, %t3_trunc %t5 = icmp ne i32 %t4, 0 ret i1 %t5 } ; However we can fold if %x/%y are constants that pass extra legality check. ; New shift amount would be 16, %x has 16 leading zeros - can fold. define i1 @t1(i64 %y, i32 %len) { ; CHECK-LABEL: @t1( ; CHECK-NEXT: [[TMP1:%.*]] = and i64 [[Y:%.*]], 4294901760 ; CHECK-NEXT: [[TMP2:%.*]] = icmp ne i64 [[TMP1]], 0 ; CHECK-NEXT: ret i1 [[TMP2]] ; %t0 = sub i32 32, %len %t1 = shl i32 65535, %t0 %t2 = add i32 %len, -16 %t2_wide = zext i32 %t2 to i64 %t3 = lshr i64 %y, %t2_wide %t3_trunc = trunc i64 %t3 to i32 %t4 = and i32 %t1, %t3_trunc %t5 = icmp ne i32 %t4, 0 ret i1 %t5 } ; Note that we indeed look at leading zeros! define i1 @t1_single_bit(i64 %y, i32 %len) { ; CHECK-LABEL: @t1_single_bit( ; CHECK-NEXT: [[TMP1:%.*]] = and i64 [[Y:%.*]], 2147483648 ; CHECK-NEXT: [[TMP2:%.*]] = icmp ne i64 [[TMP1]], 0 ; CHECK-NEXT: ret i1 [[TMP2]] ; %t0 = sub i32 32, %len %t1 = shl i32 32768, %t0 %t2 = add i32 %len, -16 %t2_wide = zext i32 %t2 to i64 %t3 = lshr i64 %y, %t2_wide %t3_trunc = trunc i64 %t3 to i32 %t4 = and i32 %t1, %t3_trunc %t5 = icmp ne i32 %t4, 0 ret i1 %t5 } ; New shift amount would be 16, %x has 15 leading zeros - can not fold. define i1 @n2(i64 %y, i32 %len) { ; CHECK-LABEL: @n2( ; CHECK-NEXT: [[T0:%.*]] = sub i32 32, [[LEN:%.*]] ; CHECK-NEXT: [[T1:%.*]] = shl i32 131071, [[T0]] ; CHECK-NEXT: [[T2:%.*]] = add i32 [[LEN]], -16 ; CHECK-NEXT: [[T2_WIDE:%.*]] = zext i32 [[T2]] to i64 ; CHECK-NEXT: [[T3:%.*]] = lshr i64 [[Y:%.*]], [[T2_WIDE]] ; CHECK-NEXT: [[T3_TRUNC:%.*]] = trunc i64 [[T3]] to i32 ; CHECK-NEXT: [[T4:%.*]] = and i32 [[T1]], [[T3_TRUNC]] ; CHECK-NEXT: [[T5:%.*]] = icmp ne i32 [[T4]], 0 ; CHECK-NEXT: ret i1 [[T5]] ; %t0 = sub i32 32, %len %t1 = shl i32 131071, %t0 %t2 = add i32 %len, -16 %t2_wide = zext i32 %t2 to i64 %t3 = lshr i64 %y, %t2_wide %t3_trunc = trunc i64 %t3 to i32 %t4 = and i32 %t1, %t3_trunc %t5 = icmp ne i32 %t4, 0 ret i1 %t5 } ; New shift amount would be 16, %y has 47 leading zeros - can fold. define i1 @t3(i32 %x, i32 %len) { ; CHECK-LABEL: @t3( ; CHECK-NEXT: [[TMP1:%.*]] = and i32 [[X:%.*]], 1 ; CHECK-NEXT: [[TMP2:%.*]] = icmp ne i32 [[TMP1]], 0 ; CHECK-NEXT: ret i1 [[TMP2]] ; %t0 = sub i32 32, %len %t1 = shl i32 %x, %t0 %t2 = add i32 %len, -16 %t2_wide = zext i32 %t2 to i64 %t3 = lshr i64 131071, %t2_wide %t3_trunc = trunc i64 %t3 to i32 %t4 = and i32 %t1, %t3_trunc %t5 = icmp ne i32 %t4, 0 ret i1 %t5 } ; Note that we indeed look at leading zeros! define i1 @t3_singlebit(i32 %x, i32 %len) { ; CHECK-LABEL: @t3_singlebit( ; CHECK-NEXT: [[TMP1:%.*]] = and i32 [[X:%.*]], 1 ; CHECK-NEXT: [[TMP2:%.*]] = icmp ne i32 [[TMP1]], 0 ; CHECK-NEXT: ret i1 [[TMP2]] ; %t0 = sub i32 32, %len %t1 = shl i32 %x, %t0 %t2 = add i32 %len, -16 %t2_wide = zext i32 %t2 to i64 %t3 = lshr i64 65536, %t2_wide %t3_trunc = trunc i64 %t3 to i32 %t4 = and i32 %t1, %t3_trunc %t5 = icmp ne i32 %t4, 0 ret i1 %t5 } ; New shift amount would be 16, %y has 48 leading zeros - can not fold. define i1 @n4(i32 %x, i32 %len) { ; CHECK-LABEL: @n4( ; CHECK-NEXT: [[T0:%.*]] = sub i32 32, [[LEN:%.*]] ; CHECK-NEXT: [[T1:%.*]] = shl i32 [[X:%.*]], [[T0]] ; CHECK-NEXT: [[T2:%.*]] = add i32 [[LEN]], -16 ; CHECK-NEXT: [[T2_WIDE:%.*]] = zext i32 [[T2]] to i64 ; CHECK-NEXT: [[T3:%.*]] = lshr i64 262143, [[T2_WIDE]] ; CHECK-NEXT: [[T3_TRUNC:%.*]] = trunc i64 [[T3]] to i32 ; CHECK-NEXT: [[T4:%.*]] = and i32 [[T1]], [[T3_TRUNC]] ; CHECK-NEXT: [[T5:%.*]] = icmp ne i32 [[T4]], 0 ; CHECK-NEXT: ret i1 [[T5]] ; %t0 = sub i32 32, %len %t1 = shl i32 %x, %t0 %t2 = add i32 %len, -16 %t2_wide = zext i32 %t2 to i64 %t3 = lshr i64 262143, %t2_wide %t3_trunc = trunc i64 %t3 to i32 %t4 = and i32 %t1, %t3_trunc %t5 = icmp ne i32 %t4, 0 ret i1 %t5 } ; While we could still deal with arbitrary values if KnownBits can answer ; the question, it isn't obvious it's worth it, so let's not for now. ;------------------------------------------------------------------------------- ; Vector tests ;------------------------------------------------------------------------------- ; New shift amount would be 16, minimal count of leading zeros in %x is 16. Ok. define <2 x i1> @t5_vec(<2 x i64> %y, <2 x i32> %len) { ; CHECK-LABEL: @t5_vec( ; CHECK-NEXT: [[TMP1:%.*]] = lshr <2 x i64> [[Y:%.*]], ; CHECK-NEXT: [[TMP2:%.*]] = and <2 x i64> [[TMP1]], ; CHECK-NEXT: [[TMP3:%.*]] = icmp ne <2 x i64> [[TMP2]], zeroinitializer ; CHECK-NEXT: ret <2 x i1> [[TMP3]] ; %t0 = sub <2 x i32> , %len %t1 = shl <2 x i32> , %t0 %t2 = add <2 x i32> %len, %t2_wide = zext <2 x i32> %t2 to <2 x i64> %t3 = lshr <2 x i64> %y, %t2_wide %t3_trunc = trunc <2 x i64> %t3 to <2 x i32> %t4 = and <2 x i32> %t1, %t3_trunc %t5 = icmp ne <2 x i32> %t4, ret <2 x i1> %t5 } ; New shift amount would be 16, minimal count of leading zeros in %x is 15, not ok to fold. define <2 x i1> @n6_vec(<2 x i64> %y, <2 x i32> %len) { ; CHECK-LABEL: @n6_vec( ; CHECK-NEXT: [[T0:%.*]] = sub <2 x i32> , [[LEN:%.*]] ; CHECK-NEXT: [[T1:%.*]] = shl <2 x i32> , [[T0]] ; CHECK-NEXT: [[T2:%.*]] = add <2 x i32> [[LEN]], ; CHECK-NEXT: [[T2_WIDE:%.*]] = zext <2 x i32> [[T2]] to <2 x i64> ; CHECK-NEXT: [[T3:%.*]] = lshr <2 x i64> [[Y:%.*]], [[T2_WIDE]] ; CHECK-NEXT: [[T3_TRUNC:%.*]] = trunc <2 x i64> [[T3]] to <2 x i32> ; CHECK-NEXT: [[T4:%.*]] = and <2 x i32> [[T1]], [[T3_TRUNC]] ; CHECK-NEXT: [[T5:%.*]] = icmp ne <2 x i32> [[T4]], zeroinitializer ; CHECK-NEXT: ret <2 x i1> [[T5]] ; %t0 = sub <2 x i32> , %len %t1 = shl <2 x i32> , %t0 %t2 = add <2 x i32> %len, %t2_wide = zext <2 x i32> %t2 to <2 x i64> %t3 = lshr <2 x i64> %y, %t2_wide %t3_trunc = trunc <2 x i64> %t3 to <2 x i32> %t4 = and <2 x i32> %t1, %t3_trunc %t5 = icmp ne <2 x i32> %t4, ret <2 x i1> %t5 } ; New shift amount would be 16, minimal count of leading zeros in %x is 47. Ok. define <2 x i1> @t7_vec(<2 x i32> %x, <2 x i32> %len) { ; CHECK-LABEL: @t7_vec( ; CHECK-NEXT: [[TMP1:%.*]] = and <2 x i32> [[X:%.*]], ; CHECK-NEXT: [[TMP2:%.*]] = icmp ne <2 x i32> [[TMP1]], zeroinitializer ; CHECK-NEXT: ret <2 x i1> [[TMP2]] ; %t0 = sub <2 x i32> , %len %t1 = shl <2 x i32> %x, %t0 %t2 = add <2 x i32> %len, %t2_wide = zext <2 x i32> %t2 to <2 x i64> %t3 = lshr <2 x i64> , %t2_wide %t3_trunc = trunc <2 x i64> %t3 to <2 x i32> %t4 = and <2 x i32> %t1, %t3_trunc %t5 = icmp ne <2 x i32> %t4, ret <2 x i1> %t5 } ; New shift amount would be 16, minimal count of leading zeros in %x is 48, not ok to fold. define <2 x i1> @n8_vec(<2 x i32> %x, <2 x i32> %len) { ; CHECK-LABEL: @n8_vec( ; CHECK-NEXT: [[T0:%.*]] = sub <2 x i32> , [[LEN:%.*]] ; CHECK-NEXT: [[T1:%.*]] = shl <2 x i32> [[X:%.*]], [[T0]] ; CHECK-NEXT: [[T2:%.*]] = add <2 x i32> [[LEN]], ; CHECK-NEXT: [[T2_WIDE:%.*]] = zext <2 x i32> [[T2]] to <2 x i64> ; CHECK-NEXT: [[T3:%.*]] = lshr <2 x i64> , [[T2_WIDE]] ; CHECK-NEXT: [[T3_TRUNC:%.*]] = trunc <2 x i64> [[T3]] to <2 x i32> ; CHECK-NEXT: [[T4:%.*]] = and <2 x i32> [[T1]], [[T3_TRUNC]] ; CHECK-NEXT: [[T5:%.*]] = icmp ne <2 x i32> [[T4]], zeroinitializer ; CHECK-NEXT: ret <2 x i1> [[T5]] ; %t0 = sub <2 x i32> , %len %t1 = shl <2 x i32> %x, %t0 %t2 = add <2 x i32> %len, %t2_wide = zext <2 x i32> %t2 to <2 x i64> %t3 = lshr <2 x i64> , %t2_wide %t3_trunc = trunc <2 x i64> %t3 to <2 x i32> %t4 = and <2 x i32> %t1, %t3_trunc %t5 = icmp ne <2 x i32> %t4, ret <2 x i1> %t5 } ;------------------------------------------------------------------------------- ; Ok if the final shift amount is exactly one less than widest bit width. define i1 @t9_highest_bit(i32 %x, i64 %y, i32 %len) { ; CHECK-LABEL: @t9_highest_bit( ; CHECK-NEXT: [[TMP1:%.*]] = zext i32 [[X:%.*]] to i64 ; CHECK-NEXT: [[TMP2:%.*]] = lshr i64 [[Y:%.*]], 63 ; CHECK-NEXT: [[TMP3:%.*]] = and i64 [[TMP2]], [[TMP1]] ; CHECK-NEXT: [[TMP4:%.*]] = icmp ne i64 [[TMP3]], 0 ; CHECK-NEXT: ret i1 [[TMP4]] ; %t0 = sub i32 64, %len %t1 = shl i32 %x, %t0 %t2 = add i32 %len, -1 %t2_wide = zext i32 %t2 to i64 %t3 = lshr i64 %y, %t2_wide %t3_trunc = trunc i64 %t3 to i32 %t4 = and i32 %t1, %t3_trunc %t5 = icmp ne i32 %t4, 0 ret i1 %t5 } ; Not highest bit. define i1 @t10_almost_highest_bit(i32 %x, i64 %y, i32 %len) { ; CHECK-LABEL: @t10_almost_highest_bit( ; CHECK-NEXT: [[T0:%.*]] = sub i32 64, [[LEN:%.*]] ; CHECK-NEXT: [[T1:%.*]] = shl i32 [[X:%.*]], [[T0]] ; CHECK-NEXT: [[T2:%.*]] = add i32 [[LEN]], -2 ; CHECK-NEXT: [[T2_WIDE:%.*]] = zext i32 [[T2]] to i64 ; CHECK-NEXT: [[T3:%.*]] = lshr i64 [[Y:%.*]], [[T2_WIDE]] ; CHECK-NEXT: [[T3_TRUNC:%.*]] = trunc i64 [[T3]] to i32 ; CHECK-NEXT: [[T4:%.*]] = and i32 [[T1]], [[T3_TRUNC]] ; CHECK-NEXT: [[T5:%.*]] = icmp ne i32 [[T4]], 0 ; CHECK-NEXT: ret i1 [[T5]] ; %t0 = sub i32 64, %len %t1 = shl i32 %x, %t0 %t2 = add i32 %len, -2 %t2_wide = zext i32 %t2 to i64 %t3 = lshr i64 %y, %t2_wide %t3_trunc = trunc i64 %t3 to i32 %t4 = and i32 %t1, %t3_trunc %t5 = icmp ne i32 %t4, 0 ret i1 %t5 } ; Ok if the final shift amount is zero. define i1 @t11_no_shift(i32 %x, i64 %y, i32 %len) { ; CHECK-LABEL: @t11_no_shift( ; CHECK-NEXT: [[TMP1:%.*]] = zext i32 [[X:%.*]] to i64 ; CHECK-NEXT: [[TMP2:%.*]] = and i64 [[TMP1]], [[Y:%.*]] ; CHECK-NEXT: [[TMP3:%.*]] = icmp ne i64 [[TMP2]], 0 ; CHECK-NEXT: ret i1 [[TMP3]] ; %t0 = sub i32 64, %len %t1 = shl i32 %x, %t0 %t2 = add i32 %len, -64 %t2_wide = zext i32 %t2 to i64 %t3 = lshr i64 %y, %t2_wide %t3_trunc = trunc i64 %t3 to i32 %t4 = and i32 %t1, %t3_trunc %t5 = icmp ne i32 %t4, 0 ret i1 %t5 } ; Not zero-shift. define i1 @t10_shift_by_one(i32 %x, i64 %y, i32 %len) { ; CHECK-LABEL: @t10_shift_by_one( ; CHECK-NEXT: [[T0:%.*]] = sub i32 64, [[LEN:%.*]] ; CHECK-NEXT: [[T1:%.*]] = shl i32 [[X:%.*]], [[T0]] ; CHECK-NEXT: [[T2:%.*]] = add i32 [[LEN]], -63 ; CHECK-NEXT: [[T2_WIDE:%.*]] = zext i32 [[T2]] to i64 ; CHECK-NEXT: [[T3:%.*]] = lshr i64 [[Y:%.*]], [[T2_WIDE]] ; CHECK-NEXT: [[T3_TRUNC:%.*]] = trunc i64 [[T3]] to i32 ; CHECK-NEXT: [[T4:%.*]] = and i32 [[T1]], [[T3_TRUNC]] ; CHECK-NEXT: [[T5:%.*]] = icmp ne i32 [[T4]], 0 ; CHECK-NEXT: ret i1 [[T5]] ; %t0 = sub i32 64, %len %t1 = shl i32 %x, %t0 %t2 = add i32 %len, -63 %t2_wide = zext i32 %t2 to i64 %t3 = lshr i64 %y, %t2_wide %t3_trunc = trunc i64 %t3 to i32 %t4 = and i32 %t1, %t3_trunc %t5 = icmp ne i32 %t4, 0 ret i1 %t5 } ; A mix of those conditions is ok. define <2 x i1> @t11_zero_and_almost_bitwidth(<2 x i32> %x, <2 x i64> %y, <2 x i32> %len) { ; CHECK-LABEL: @t11_zero_and_almost_bitwidth( ; CHECK-NEXT: [[T0:%.*]] = sub <2 x i32> , [[LEN:%.*]] ; CHECK-NEXT: [[T1:%.*]] = shl <2 x i32> [[X:%.*]], [[T0]] ; CHECK-NEXT: [[T2:%.*]] = add <2 x i32> [[LEN]], ; CHECK-NEXT: [[T2_WIDE:%.*]] = zext <2 x i32> [[T2]] to <2 x i64> ; CHECK-NEXT: [[T3:%.*]] = lshr <2 x i64> [[Y:%.*]], [[T2_WIDE]] ; CHECK-NEXT: [[T3_TRUNC:%.*]] = trunc <2 x i64> [[T3]] to <2 x i32> ; CHECK-NEXT: [[T4:%.*]] = and <2 x i32> [[T1]], [[T3_TRUNC]] ; CHECK-NEXT: [[T5:%.*]] = icmp ne <2 x i32> [[T4]], zeroinitializer ; CHECK-NEXT: ret <2 x i1> [[T5]] ; %t0 = sub <2 x i32> , %len %t1 = shl <2 x i32> %x, %t0 %t2 = add <2 x i32> %len, %t2_wide = zext <2 x i32> %t2 to <2 x i64> %t3 = lshr <2 x i64> %y, %t2_wide %t3_trunc = trunc <2 x i64> %t3 to <2 x i32> %t4 = and <2 x i32> %t1, %t3_trunc %t5 = icmp ne <2 x i32> %t4, ret <2 x i1> %t5 } define <2 x i1> @n12_bad(<2 x i32> %x, <2 x i64> %y, <2 x i32> %len) { ; CHECK-LABEL: @n12_bad( ; CHECK-NEXT: [[T0:%.*]] = sub <2 x i32> , [[LEN:%.*]] ; CHECK-NEXT: [[T1:%.*]] = shl <2 x i32> [[X:%.*]], [[T0]] ; CHECK-NEXT: [[T2:%.*]] = add <2 x i32> [[LEN]], ; CHECK-NEXT: [[T2_WIDE:%.*]] = zext <2 x i32> [[T2]] to <2 x i64> ; CHECK-NEXT: [[T3:%.*]] = lshr <2 x i64> [[Y:%.*]], [[T2_WIDE]] ; CHECK-NEXT: [[T3_TRUNC:%.*]] = trunc <2 x i64> [[T3]] to <2 x i32> ; CHECK-NEXT: [[T4:%.*]] = and <2 x i32> [[T1]], [[T3_TRUNC]] ; CHECK-NEXT: [[T5:%.*]] = icmp ne <2 x i32> [[T4]], zeroinitializer ; CHECK-NEXT: ret <2 x i1> [[T5]] ; %t0 = sub <2 x i32> , %len %t1 = shl <2 x i32> %x, %t0 %t2 = add <2 x i32> %len, %t2_wide = zext <2 x i32> %t2 to <2 x i64> %t3 = lshr <2 x i64> %y, %t2_wide %t3_trunc = trunc <2 x i64> %t3 to <2 x i32> %t4 = and <2 x i32> %t1, %t3_trunc %t5 = icmp ne <2 x i32> %t4, ret <2 x i1> %t5 } ;------------------------------------------------------------------------------; ; Ok if one of the values being shifted is 1 define i1 @t13_x_is_one(i64 %y, i32 %len) { ; CHECK-LABEL: @t13_x_is_one( ; CHECK-NEXT: [[TMP1:%.*]] = and i64 [[Y:%.*]], 65536 ; CHECK-NEXT: [[TMP2:%.*]] = icmp ne i64 [[TMP1]], 0 ; CHECK-NEXT: ret i1 [[TMP2]] ; %t0 = sub i32 32, %len %t1 = shl i32 1, %t0 %t2 = add i32 %len, -16 %t2_wide = zext i32 %t2 to i64 %t3 = lshr i64 %y, %t2_wide %t3_trunc = trunc i64 %t3 to i32 %t4 = and i32 %t1, %t3_trunc %t5 = icmp ne i32 %t4, 0 ret i1 %t5 } define i1 @t14_x_is_one(i32 %x, i32 %len) { ; CHECK-LABEL: @t14_x_is_one( ; CHECK-NEXT: ret i1 false ; %t0 = sub i32 32, %len %t1 = shl i32 %x, %t0 %t2 = add i32 %len, -16 %t2_wide = zext i32 %t2 to i64 %t3 = lshr i64 1, %t2_wide %t3_trunc = trunc i64 %t3 to i32 %t4 = and i32 %t1, %t3_trunc %t5 = icmp ne i32 %t4, 0 ret i1 %t5 } define <2 x i1> @t15_vec_x_is_one_or_zero(<2 x i64> %y, <2 x i32> %len) { ; CHECK-LABEL: @t15_vec_x_is_one_or_zero( ; CHECK-NEXT: [[TMP1:%.*]] = lshr <2 x i64> [[Y:%.*]], ; CHECK-NEXT: [[TMP2:%.*]] = and <2 x i64> [[TMP1]], ; CHECK-NEXT: [[TMP3:%.*]] = icmp ne <2 x i64> [[TMP2]], zeroinitializer ; CHECK-NEXT: ret <2 x i1> [[TMP3]] ; %t0 = sub <2 x i32> , %len %t1 = shl <2 x i32> , %t0 %t2 = add <2 x i32> %len, %t2_wide = zext <2 x i32> %t2 to <2 x i64> %t3 = lshr <2 x i64> %y, %t2_wide %t3_trunc = trunc <2 x i64> %t3 to <2 x i32> %t4 = and <2 x i32> %t1, %t3_trunc %t5 = icmp ne <2 x i32> %t4, ret <2 x i1> %t5 } define <2 x i1> @t16_vec_y_is_one_or_zero(<2 x i32> %x, <2 x i32> %len) { ; CHECK-LABEL: @t16_vec_y_is_one_or_zero( ; CHECK-NEXT: ret <2 x i1> zeroinitializer ; %t0 = sub <2 x i32> , %len %t1 = shl <2 x i32> %x, %t0 %t2 = add <2 x i32> %len, %t2_wide = zext <2 x i32> %t2 to <2 x i64> %t3 = lshr <2 x i64> , %t2_wide %t3_trunc = trunc <2 x i64> %t3 to <2 x i32> %t4 = and <2 x i32> %t1, %t3_trunc %t5 = icmp ne <2 x i32> %t4, ret <2 x i1> %t5 } ;------------------------------------------------------------------------------; ; All other tests - extra uses, etc are already covered in ; shift-amount-reassociation-in-bittest-with-truncation-shl.ll and ; shift-amount-reassociation-in-bittest.ll ; And that's the main motivational pattern: define i1 @rawspeed_signbit(i64 %storage, i32 %nbits) { ; CHECK-LABEL: @rawspeed_signbit( ; CHECK-NEXT: [[TMP1:%.*]] = icmp sgt i64 [[STORAGE:%.*]], -1 ; CHECK-NEXT: ret i1 [[TMP1]] ; %skipnbits = sub nsw i32 64, %nbits %skipnbitswide = zext i32 %skipnbits to i64 %datawide = lshr i64 %storage, %skipnbitswide %data = trunc i64 %datawide to i32 %nbitsminusone = add nsw i32 %nbits, -1 %bitmask = shl i32 1, %nbitsminusone %bitmasked = and i32 %bitmask, %data %isbitunset = icmp eq i32 %bitmasked, 0 ret i1 %isbitunset }