| ; NOTE: Assertions have been autogenerated by utils/update_test_checks.py |
| ; RUN: opt -instcombine -S < %s | FileCheck %s |
| |
| ; Transforms for unsigned saturated subtraction idioms are tested here. |
| ; In all cases, we want to form a canonical min/max op (the compare and |
| ; select operands are the same), so that is recognized by the backend. |
| ; The backend recognition is tested in test/CodeGen/X86/psubus.ll. |
| |
| declare void @use(i64) |
| |
| ; (a > b) ? a - b : 0 -> ((a > b) ? a : b) - b) |
| |
| define i64 @max_sub_ugt(i64 %a, i64 %b) { |
| ; CHECK-LABEL: @max_sub_ugt( |
| ; CHECK-NEXT: [[TMP1:%.*]] = icmp ugt i64 [[A:%.*]], [[B:%.*]] |
| ; CHECK-NEXT: [[TMP2:%.*]] = select i1 [[TMP1]], i64 [[A]], i64 [[B]] |
| ; CHECK-NEXT: [[TMP3:%.*]] = sub i64 [[TMP2]], [[B]] |
| ; CHECK-NEXT: ret i64 [[TMP3]] |
| ; |
| %cmp = icmp ugt i64 %a, %b |
| %sub = sub i64 %a, %b |
| %sel = select i1 %cmp, i64 %sub ,i64 0 |
| ret i64 %sel |
| } |
| |
| ; (a >= b) ? a - b : 0 -> ((a >= b) ? a : b) - b) |
| |
| define i64 @max_sub_uge(i64 %a, i64 %b) { |
| ; CHECK-LABEL: @max_sub_uge( |
| ; CHECK-NEXT: [[TMP1:%.*]] = icmp ult i64 [[A:%.*]], [[B:%.*]] |
| ; CHECK-NEXT: [[TMP2:%.*]] = select i1 [[TMP1]], i64 [[B]], i64 [[A]] |
| ; CHECK-NEXT: [[TMP3:%.*]] = sub i64 [[TMP2]], [[B]] |
| ; CHECK-NEXT: ret i64 [[TMP3]] |
| ; |
| %cmp = icmp uge i64 %a, %b |
| %sub = sub i64 %a, %b |
| %sel = select i1 %cmp, i64 %sub ,i64 0 |
| ret i64 %sel |
| } |
| |
| ; Again, with vectors: |
| ; (a > b) ? a - b : 0 -> ((a > b) ? a : b) - b) |
| |
| define <4 x i32> @max_sub_ugt_vec(<4 x i32> %a, <4 x i32> %b) { |
| ; CHECK-LABEL: @max_sub_ugt_vec( |
| ; CHECK-NEXT: [[TMP1:%.*]] = icmp ugt <4 x i32> [[A:%.*]], [[B:%.*]] |
| ; CHECK-NEXT: [[TMP2:%.*]] = select <4 x i1> [[TMP1]], <4 x i32> [[A]], <4 x i32> [[B]] |
| ; CHECK-NEXT: [[TMP3:%.*]] = sub <4 x i32> [[TMP2]], [[B]] |
| ; CHECK-NEXT: ret <4 x i32> [[TMP3]] |
| ; |
| %cmp = icmp ugt <4 x i32> %a, %b |
| %sub = sub <4 x i32> %a, %b |
| %sel = select <4 x i1> %cmp, <4 x i32> %sub, <4 x i32> zeroinitializer |
| ret <4 x i32> %sel |
| } |
| |
| ; Use extra ops to thwart icmp swapping canonicalization. |
| ; (b < a) ? a - b : 0 -> ((a > b) ? a : b) - b) |
| |
| define i64 @max_sub_ult(i64 %a, i64 %b) { |
| ; CHECK-LABEL: @max_sub_ult( |
| ; CHECK-NEXT: [[TMP1:%.*]] = icmp ult i64 [[B:%.*]], [[A:%.*]] |
| ; CHECK-NEXT: [[TMP2:%.*]] = select i1 [[TMP1]], i64 [[A]], i64 [[B]] |
| ; CHECK-NEXT: [[TMP3:%.*]] = sub i64 [[TMP2]], [[B]] |
| ; CHECK-NEXT: [[EXTRASUB:%.*]] = sub i64 [[B]], [[A]] |
| ; CHECK-NEXT: call void @use(i64 [[EXTRASUB]]) |
| ; CHECK-NEXT: ret i64 [[TMP3]] |
| ; |
| %cmp = icmp ult i64 %b, %a |
| %sub = sub i64 %a, %b |
| %sel = select i1 %cmp, i64 %sub ,i64 0 |
| %extrasub = sub i64 %b, %a |
| call void @use(i64 %extrasub) |
| ret i64 %sel |
| } |
| |
| ; (b > a) ? 0 : a - b -> ((a > b) ? a : b) - b) |
| |
| define i64 @max_sub_ugt_sel_swapped(i64 %a, i64 %b) { |
| ; CHECK-LABEL: @max_sub_ugt_sel_swapped( |
| ; CHECK-NEXT: [[TMP1:%.*]] = icmp ugt i64 [[B:%.*]], [[A:%.*]] |
| ; CHECK-NEXT: [[TMP2:%.*]] = select i1 [[TMP1]], i64 [[B]], i64 [[A]] |
| ; CHECK-NEXT: [[TMP3:%.*]] = sub i64 [[TMP2]], [[B]] |
| ; CHECK-NEXT: [[EXTRASUB:%.*]] = sub i64 [[B]], [[A]] |
| ; CHECK-NEXT: call void @use(i64 [[EXTRASUB]]) |
| ; CHECK-NEXT: ret i64 [[TMP3]] |
| ; |
| %cmp = icmp ugt i64 %b, %a |
| %sub = sub i64 %a, %b |
| %sel = select i1 %cmp, i64 0 ,i64 %sub |
| %extrasub = sub i64 %b, %a |
| call void @use(i64 %extrasub) |
| ret i64 %sel |
| } |
| |
| ; (a < b) ? 0 : a - b -> ((a > b) ? a : b) - b) |
| |
| define i64 @max_sub_ult_sel_swapped(i64 %a, i64 %b) { |
| ; CHECK-LABEL: @max_sub_ult_sel_swapped( |
| ; CHECK-NEXT: [[TMP1:%.*]] = icmp ult i64 [[A:%.*]], [[B:%.*]] |
| ; CHECK-NEXT: [[TMP2:%.*]] = select i1 [[TMP1]], i64 [[B]], i64 [[A]] |
| ; CHECK-NEXT: [[TMP3:%.*]] = sub i64 [[TMP2]], [[B]] |
| ; CHECK-NEXT: ret i64 [[TMP3]] |
| ; |
| %cmp = icmp ult i64 %a, %b |
| %sub = sub i64 %a, %b |
| %sel = select i1 %cmp, i64 0 ,i64 %sub |
| ret i64 %sel |
| } |
| |
| ; ((a > b) ? b - a : 0) -> (b - ((a > b) ? a : b)) |
| |
| define i64 @neg_max_sub_ugt(i64 %a, i64 %b) { |
| ; CHECK-LABEL: @neg_max_sub_ugt( |
| ; CHECK-NEXT: [[TMP1:%.*]] = icmp ugt i64 [[A:%.*]], [[B:%.*]] |
| ; CHECK-NEXT: [[TMP2:%.*]] = select i1 [[TMP1]], i64 [[A]], i64 [[B]] |
| ; CHECK-NEXT: [[TMP3:%.*]] = sub i64 [[B]], [[TMP2]] |
| ; CHECK-NEXT: [[EXTRASUB:%.*]] = sub i64 [[A]], [[B]] |
| ; CHECK-NEXT: call void @use(i64 [[EXTRASUB]]) |
| ; CHECK-NEXT: ret i64 [[TMP3]] |
| ; |
| %cmp = icmp ugt i64 %a, %b |
| %sub = sub i64 %b, %a |
| %sel = select i1 %cmp, i64 %sub ,i64 0 |
| %extrasub = sub i64 %a, %b |
| call void @use(i64 %extrasub) |
| ret i64 %sel |
| } |
| |
| ; ((b < a) ? b - a : 0) -> - ((a > b) ? a : b) - b) |
| |
| define i64 @neg_max_sub_ult(i64 %a, i64 %b) { |
| ; CHECK-LABEL: @neg_max_sub_ult( |
| ; CHECK-NEXT: [[TMP1:%.*]] = icmp ugt i64 [[A:%.*]], [[B:%.*]] |
| ; CHECK-NEXT: [[TMP2:%.*]] = select i1 [[TMP1]], i64 [[A]], i64 [[B]] |
| ; CHECK-NEXT: [[TMP3:%.*]] = sub i64 [[B]], [[TMP2]] |
| ; CHECK-NEXT: ret i64 [[TMP3]] |
| ; |
| %cmp = icmp ult i64 %b, %a |
| %sub = sub i64 %b, %a |
| %sel = select i1 %cmp, i64 %sub ,i64 0 |
| ret i64 %sel |
| } |
| |
| ; ((b > a) ? 0 : b - a) -> - ((a > b) ? a : b) - b) |
| |
| define i64 @neg_max_sub_ugt_sel_swapped(i64 %a, i64 %b) { |
| ; CHECK-LABEL: @neg_max_sub_ugt_sel_swapped( |
| ; CHECK-NEXT: [[TMP1:%.*]] = icmp ult i64 [[A:%.*]], [[B:%.*]] |
| ; CHECK-NEXT: [[TMP2:%.*]] = select i1 [[TMP1]], i64 [[B]], i64 [[A]] |
| ; CHECK-NEXT: [[TMP3:%.*]] = sub i64 [[B]], [[TMP2]] |
| ; CHECK-NEXT: ret i64 [[TMP3]] |
| ; |
| %cmp = icmp ugt i64 %b, %a |
| %sub = sub i64 %b, %a |
| %sel = select i1 %cmp, i64 0 ,i64 %sub |
| ret i64 %sel |
| } |
| |
| ; ((a < b) ? 0 : b - a) -> - ((a > b) ? a : b) - b) |
| |
| define i64 @neg_max_sub_ult_sel_swapped(i64 %a, i64 %b) { |
| ; CHECK-LABEL: @neg_max_sub_ult_sel_swapped( |
| ; CHECK-NEXT: [[TMP1:%.*]] = icmp ult i64 [[A:%.*]], [[B:%.*]] |
| ; CHECK-NEXT: [[TMP2:%.*]] = select i1 [[TMP1]], i64 [[B]], i64 [[A]] |
| ; CHECK-NEXT: [[TMP3:%.*]] = sub i64 [[B]], [[TMP2]] |
| ; CHECK-NEXT: [[EXTRASUB:%.*]] = sub i64 [[A]], [[B]] |
| ; CHECK-NEXT: call void @use(i64 [[EXTRASUB]]) |
| ; CHECK-NEXT: ret i64 [[TMP3]] |
| ; |
| %cmp = icmp ult i64 %a, %b |
| %sub = sub i64 %b, %a |
| %sel = select i1 %cmp, i64 0 ,i64 %sub |
| %extrasub = sub i64 %a, %b |
| call void @use(i64 %extrasub) |
| ret i64 %sel |
| } |
| |