[InstCombine] Tests for ~A - Min/Max(~A, O) -> Max/Min(A, ~O) - A. NFC

2 files changed, 359 insertions, 35 deletions

diff --git a/llvm/test/Transforms/InstCombine/max-of-nots.ll b/llvm/test/Transforms/InstCombine/max-of-nots.ll
index 3e38718bf58..b8643f5002e 100644
--- a/llvm/test/Transforms/InstCombine/max-of-nots.ll
+++ b/llvm/test/Transforms/InstCombine/max-of-nots.ll
@@ -161,41 +161,6 @@ define i8 @umin3_not_all_ops_extra_uses(i8 %x, i8 %y, i8 %z) {
   ret i8 %minxyz
 }
 
-define void @umin3_not_all_ops_extra_uses_invert_subs(i8 %x, i8 %y, i8 %z) {
-; CHECK-LABEL: @umin3_not_all_ops_extra_uses_invert_subs(
-; CHECK-NEXT:    [[XN:%.*]] = xor i8 [[X:%.*]], -1
-; CHECK-NEXT:    [[YN:%.*]] = xor i8 [[Y:%.*]], -1
-; CHECK-NEXT:    [[ZN:%.*]] = xor i8 [[Z:%.*]], -1
-; CHECK-NEXT:    [[CMPXZ:%.*]] = icmp ult i8 [[XN]], [[ZN]]
-; CHECK-NEXT:    [[MINXZ:%.*]] = select i1 [[CMPXZ]], i8 [[XN]], i8 [[ZN]]
-; CHECK-NEXT:    [[CMPXYZ:%.*]] = icmp ult i8 [[MINXZ]], [[YN]]
-; CHECK-NEXT:    [[MINXYZ:%.*]] = select i1 [[CMPXYZ]], i8 [[MINXZ]], i8 [[YN]]
-; CHECK-NEXT:    [[XMIN:%.*]] = sub i8 [[XN]], [[MINXYZ]]
-; CHECK-NEXT:    [[YMIN:%.*]] = sub i8 [[YN]], [[MINXYZ]]
-; CHECK-NEXT:    [[ZMIN:%.*]] = sub i8 [[ZN]], [[MINXYZ]]
-; CHECK-NEXT:    call void @use8(i8 [[MINXYZ]])
-; CHECK-NEXT:    call void @use8(i8 [[XMIN]])
-; CHECK-NEXT:    call void @use8(i8 [[YMIN]])
-; CHECK-NEXT:    call void @use8(i8 [[ZMIN]])
-; CHECK-NEXT:    ret void
-;
-  %xn = xor i8 %x, -1
-  %yn = xor i8 %y, -1
-  %zn = xor i8 %z, -1
-  %cmpxz = icmp ult i8 %xn, %zn
-  %minxz = select i1 %cmpxz, i8 %xn, i8 %zn
-  %cmpxyz = icmp ult i8 %minxz, %yn
-  %minxyz = select i1 %cmpxyz, i8 %minxz, i8 %yn
-  %xmin = sub i8 %xn, %minxyz
-  %ymin = sub i8 %yn, %minxyz
-  %zmin = sub i8 %zn, %minxyz
-  call void @use8(i8 %minxyz)
-  call void @use8(i8 %xmin)
-  call void @use8(i8 %ymin)
-  call void @use8(i8 %zmin)
-  ret void
-}
-
 define i32 @compute_min_3(i32 %x, i32 %y, i32 %z) {
 ; CHECK-LABEL: @compute_min_3(
 ; CHECK-NEXT:    [[TMP1:%.*]] = icmp sgt i32 [[Y:%.*]], [[X:%.*]]
diff --git a/llvm/test/Transforms/InstCombine/sub-minmax.ll b/llvm/test/Transforms/InstCombine/sub-minmax.ll
new file mode 100644
index 00000000000..43a4cf18358
--- /dev/null
+++ b/llvm/test/Transforms/InstCombine/sub-minmax.ll
@@ -0,0 +1,359 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt < %s -instcombine -S | FileCheck %s
+
+define i32 @max_na_b_minux_na(i32 %A, i32 %B) {
+; CHECK-LABEL: @max_na_b_minux_na(
+; CHECK-NEXT:    [[NOT:%.*]] = xor i32 [[A:%.*]], -1
+; CHECK-NEXT:    [[L0:%.*]] = icmp ult i32 [[NOT]], [[B:%.*]]
+; CHECK-NEXT:    [[L1:%.*]] = select i1 [[L0]], i32 [[NOT]], i32 [[B]]
+; CHECK-NEXT:    [[X:%.*]] = sub i32 [[L1]], [[NOT]]
+; CHECK-NEXT:    ret i32 [[X]]
+;
+  %not = xor i32 %A, -1
+  %l0 = icmp ult i32 %not, %B
+  %l1 = select i1 %l0, i32 %not, i32 %B
+  %x = sub i32 %l1, %not
+  ret i32 %x
+}
+
+define i32 @na_minus_max_na_b(i32 %A, i32 %B) {
+; CHECK-LABEL: @na_minus_max_na_b(
+; CHECK-NEXT:    [[NOT:%.*]] = xor i32 [[A:%.*]], -1
+; CHECK-NEXT:    [[L0:%.*]] = icmp ult i32 [[NOT]], [[B:%.*]]
+; CHECK-NEXT:    [[L1:%.*]] = select i1 [[L0]], i32 [[NOT]], i32 [[B]]
+; CHECK-NEXT:    [[X:%.*]] = sub i32 [[NOT]], [[L1]]
+; CHECK-NEXT:    ret i32 [[X]]
+;
+  %not = xor i32 %A, -1
+  %l0 = icmp ult i32 %not, %B
+  %l1 = select i1 %l0, i32 %not, i32 %B
+  %x = sub i32 %not, %l1
+  ret i32 %x
+}
+
+define i32 @max_b_na_minus_na(i32 %A, i32 %B) {
+; CHECK-LABEL: @max_b_na_minus_na(
+; CHECK-NEXT:    [[NOT:%.*]] = xor i32 [[A:%.*]], -1
+; CHECK-NEXT:    [[L0:%.*]] = icmp ugt i32 [[NOT]], [[B:%.*]]
+; CHECK-NEXT:    [[L1:%.*]] = select i1 [[L0]], i32 [[B]], i32 [[NOT]]
+; CHECK-NEXT:    [[X:%.*]] = sub i32 [[L1]], [[NOT]]
+; CHECK-NEXT:    ret i32 [[X]]
+;
+  %not = xor i32 %A, -1
+  %l0 = icmp ugt i32 %not, %B
+  %l1 = select i1 %l0, i32 %B, i32 %not
+  %x = sub i32 %l1, %not
+  ret i32 %x
+}
+
+define i32 @na_minus_max_b_na(i32 %A, i32 %B) {
+; CHECK-LABEL: @na_minus_max_b_na(
+; CHECK-NEXT:    [[NOT:%.*]] = xor i32 [[A:%.*]], -1
+; CHECK-NEXT:    [[L0:%.*]] = icmp ugt i32 [[NOT]], [[B:%.*]]
+; CHECK-NEXT:    [[L1:%.*]] = select i1 [[L0]], i32 [[B]], i32 [[NOT]]
+; CHECK-NEXT:    [[X:%.*]] = sub i32 [[NOT]], [[L1]]
+; CHECK-NEXT:    ret i32 [[X]]
+;
+  %not = xor i32 %A, -1
+  %l0 = icmp ugt i32 %not, %B
+  %l1 = select i1 %l0, i32 %B, i32 %not
+  %x = sub i32 %not, %l1
+  ret i32 %x
+}
+
+
+define i32 @max_na_bi_minux_na(i32 %A, i32 %Bi) {
+; CHECK-LABEL: @max_na_bi_minux_na(
+; CHECK-NEXT:    [[TMP1:%.*]] = icmp ult i32 [[A:%.*]], [[BI:%.*]]
+; CHECK-NEXT:    [[TMP2:%.*]] = select i1 [[TMP1]], i32 [[BI]], i32 [[A]]
+; CHECK-NEXT:    [[X:%.*]] = sub i32 [[A]], [[TMP2]]
+; CHECK-NEXT:    ret i32 [[X]]
+;
+  %B =  xor i32 %Bi, -1
+  %not = xor i32 %A, -1
+  %l0 = icmp ult i32 %not, %B
+  %l1 = select i1 %l0, i32 %not, i32 %B
+  %x = sub i32 %l1, %not
+  ret i32 %x
+}
+
+define i32 @na_minus_max_na_bi(i32 %A, i32 %Bi) {
+; CHECK-LABEL: @na_minus_max_na_bi(
+; CHECK-NEXT:    [[TMP1:%.*]] = icmp ult i32 [[A:%.*]], [[BI:%.*]]
+; CHECK-NEXT:    [[TMP2:%.*]] = select i1 [[TMP1]], i32 [[BI]], i32 [[A]]
+; CHECK-NEXT:    [[X:%.*]] = sub i32 [[TMP2]], [[A]]
+; CHECK-NEXT:    ret i32 [[X]]
+;
+  %B =  xor i32 %Bi, -1
+  %not = xor i32 %A, -1
+  %l0 = icmp ult i32 %not, %B
+  %l1 = select i1 %l0, i32 %not, i32 %B
+  %x = sub i32 %not, %l1
+  ret i32 %x
+}
+
+define i32 @max_bi_na_minus_na(i32 %A, i32 %Bi) {
+; CHECK-LABEL: @max_bi_na_minus_na(
+; CHECK-NEXT:    [[TMP1:%.*]] = icmp ult i32 [[A:%.*]], [[BI:%.*]]
+; CHECK-NEXT:    [[TMP2:%.*]] = select i1 [[TMP1]], i32 [[BI]], i32 [[A]]
+; CHECK-NEXT:    [[X:%.*]] = sub i32 [[A]], [[TMP2]]
+; CHECK-NEXT:    ret i32 [[X]]
+;
+  %B =  xor i32 %Bi, -1
+  %not = xor i32 %A, -1
+  %l0 = icmp ugt i32 %not, %B
+  %l1 = select i1 %l0, i32 %B, i32 %not
+  %x = sub i32 %l1, %not
+  ret i32 %x
+}
+
+define i32 @na_minus_max_bi_na(i32 %A, i32 %Bi) {
+; CHECK-LABEL: @na_minus_max_bi_na(
+; CHECK-NEXT:    [[TMP1:%.*]] = icmp ult i32 [[A:%.*]], [[BI:%.*]]
+; CHECK-NEXT:    [[TMP2:%.*]] = select i1 [[TMP1]], i32 [[BI]], i32 [[A]]
+; CHECK-NEXT:    [[X:%.*]] = sub i32 [[TMP2]], [[A]]
+; CHECK-NEXT:    ret i32 [[X]]
+;
+  %B =  xor i32 %Bi, -1
+  %not = xor i32 %A, -1
+  %l0 = icmp ugt i32 %not, %B
+  %l1 = select i1 %l0, i32 %B, i32 %not
+  %x = sub i32 %not, %l1
+  ret i32 %x
+}
+
+
+define i32 @max_na_bi_minux_na_use(i32 %A, i32 %Bi) {
+; CHECK-LABEL: @max_na_bi_minux_na_use(
+; CHECK-NEXT:    [[NOT:%.*]] = xor i32 [[A:%.*]], -1
+; CHECK-NEXT:    [[L0:%.*]] = icmp ult i32 [[NOT]], 31
+; CHECK-NEXT:    [[L1:%.*]] = select i1 [[L0]], i32 [[NOT]], i32 31
+; CHECK-NEXT:    [[X:%.*]] = sub i32 [[L1]], [[NOT]]
+; CHECK-NEXT:    call void @use32(i32 [[L1]])
+; CHECK-NEXT:    ret i32 [[X]]
+;
+  %not = xor i32 %A, -1
+  %l0 = icmp ult i32 %not, 31
+  %l1 = select i1 %l0, i32 %not, i32 31
+  %x = sub i32 %l1, %not
+  call void @use32(i32 %l1)
+  ret i32 %x
+}
+
+define i32 @na_minus_max_na_bi_use(i32 %A, i32 %Bi) {
+; CHECK-LABEL: @na_minus_max_na_bi_use(
+; CHECK-NEXT:    [[NOT:%.*]] = xor i32 [[A:%.*]], -1
+; CHECK-NEXT:    [[L0:%.*]] = icmp ult i32 [[NOT]], 31
+; CHECK-NEXT:    [[L1:%.*]] = select i1 [[L0]], i32 [[NOT]], i32 31
+; CHECK-NEXT:    [[X:%.*]] = sub i32 [[NOT]], [[L1]]
+; CHECK-NEXT:    call void @use32(i32 [[L1]])
+; CHECK-NEXT:    ret i32 [[X]]
+;
+  %not = xor i32 %A, -1
+  %l0 = icmp ult i32 %not, 31
+  %l1 = select i1 %l0, i32 %not, i32 31
+  %x = sub i32 %not, %l1
+  call void @use32(i32 %l1)
+  ret i32 %x
+}
+
+define i32 @max_bi_na_minus_na_use(i32 %A, i32 %Bi) {
+; CHECK-LABEL: @max_bi_na_minus_na_use(
+; CHECK-NEXT:    [[TMP1:%.*]] = icmp ult i32 [[A:%.*]], [[BI:%.*]]
+; CHECK-NEXT:    [[TMP2:%.*]] = select i1 [[TMP1]], i32 [[BI]], i32 [[A]]
+; CHECK-NEXT:    [[L1:%.*]] = xor i32 [[TMP2]], -1
+; CHECK-NEXT:    [[X:%.*]] = sub i32 [[A]], [[TMP2]]
+; CHECK-NEXT:    call void @use32(i32 [[L1]])
+; CHECK-NEXT:    ret i32 [[X]]
+;
+  %not = xor i32 %A, -1
+  %B = xor i32 %Bi, -1
+  %l0 = icmp ult i32 %B, %not
+  %l1 = select i1 %l0, i32 %B, i32 %not
+  %x = sub i32 %l1, %not
+  call void @use32(i32 %l1)
+  ret i32 %x
+}
+
+define i32 @na_minus_max_bi_na_use(i32 %A, i32 %Bi) {
+; CHECK-LABEL: @na_minus_max_bi_na_use(
+; CHECK-NEXT:    [[TMP1:%.*]] = icmp ult i32 [[A:%.*]], [[BI:%.*]]
+; CHECK-NEXT:    [[TMP2:%.*]] = select i1 [[TMP1]], i32 [[BI]], i32 [[A]]
+; CHECK-NEXT:    [[L1:%.*]] = xor i32 [[TMP2]], -1
+; CHECK-NEXT:    [[X:%.*]] = sub i32 [[TMP2]], [[A]]
+; CHECK-NEXT:    call void @use32(i32 [[L1]])
+; CHECK-NEXT:    ret i32 [[X]]
+;
+  %not = xor i32 %A, -1
+  %B = xor i32 %Bi, -1
+  %l0 = icmp ult i32 %B, %not
+  %l1 = select i1 %l0, i32 %B, i32 %not
+  %x = sub i32 %not, %l1
+  call void @use32(i32 %l1)
+  ret i32 %x
+}
+
+
+define i32 @max_na_bi_minux_na_use2(i32 %A, i32 %Bi) {
+; CHECK-LABEL: @max_na_bi_minux_na_use2(
+; CHECK-NEXT:    [[NOT:%.*]] = xor i32 [[A:%.*]], -1
+; CHECK-NEXT:    [[L0:%.*]] = icmp ult i32 [[NOT]], 31
+; CHECK-NEXT:    [[L1:%.*]] = select i1 [[L0]], i32 [[NOT]], i32 31
+; CHECK-NEXT:    [[X:%.*]] = sub i32 [[L1]], [[NOT]]
+; CHECK-NEXT:    call void @use32(i32 [[L1]])
+; CHECK-NEXT:    call void @use32(i32 [[NOT]])
+; CHECK-NEXT:    ret i32 [[X]]
+;
+  %not = xor i32 %A, -1
+  %l0 = icmp ult i32 %not, 31
+  %l1 = select i1 %l0, i32 %not, i32 31
+  %x = sub i32 %l1, %not
+  call void @use32(i32 %l1)
+  call void @use32(i32 %not)
+  ret i32 %x
+}
+
+define i32 @na_minus_max_na_bi_use2(i32 %A, i32 %Bi) {
+; CHECK-LABEL: @na_minus_max_na_bi_use2(
+; CHECK-NEXT:    [[NOT:%.*]] = xor i32 [[A:%.*]], -1
+; CHECK-NEXT:    [[L0:%.*]] = icmp ult i32 [[NOT]], 31
+; CHECK-NEXT:    [[L1:%.*]] = select i1 [[L0]], i32 [[NOT]], i32 31
+; CHECK-NEXT:    [[X:%.*]] = sub i32 [[NOT]], [[L1]]
+; CHECK-NEXT:    call void @use32(i32 [[L1]])
+; CHECK-NEXT:    call void @use32(i32 [[NOT]])
+; CHECK-NEXT:    ret i32 [[X]]
+;
+  %not = xor i32 %A, -1
+  %l0 = icmp ult i32 %not, 31
+  %l1 = select i1 %l0, i32 %not, i32 31
+  %x = sub i32 %not, %l1
+  call void @use32(i32 %l1)
+  call void @use32(i32 %not)
+  ret i32 %x
+}
+
+define i32 @max_bi_na_minus_na_use2(i32 %A, i32 %Bi) {
+; CHECK-LABEL: @max_bi_na_minus_na_use2(
+; CHECK-NEXT:    [[NOT:%.*]] = xor i32 [[A:%.*]], -1
+; CHECK-NEXT:    [[TMP1:%.*]] = icmp ult i32 [[A]], [[BI:%.*]]
+; CHECK-NEXT:    [[TMP2:%.*]] = select i1 [[TMP1]], i32 [[BI]], i32 [[A]]
+; CHECK-NEXT:    [[L1:%.*]] = xor i32 [[TMP2]], -1
+; CHECK-NEXT:    [[X:%.*]] = sub i32 [[A]], [[TMP2]]
+; CHECK-NEXT:    call void @use32(i32 [[L1]])
+; CHECK-NEXT:    call void @use32(i32 [[NOT]])
+; CHECK-NEXT:    ret i32 [[X]]
+;
+  %not = xor i32 %A, -1
+  %B = xor i32 %Bi, -1
+  %l0 = icmp ult i32 %B, %not
+  %l1 = select i1 %l0, i32 %B, i32 %not
+  %x = sub i32 %l1, %not
+  call void @use32(i32 %l1)
+  call void @use32(i32 %not)
+  ret i32 %x
+}
+
+define i32 @na_minus_max_bi_na_use2(i32 %A, i32 %Bi) {
+; CHECK-LABEL: @na_minus_max_bi_na_use2(
+; CHECK-NEXT:    [[NOT:%.*]] = xor i32 [[A:%.*]], -1
+; CHECK-NEXT:    [[TMP1:%.*]] = icmp ult i32 [[A]], [[BI:%.*]]
+; CHECK-NEXT:    [[TMP2:%.*]] = select i1 [[TMP1]], i32 [[BI]], i32 [[A]]
+; CHECK-NEXT:    [[L1:%.*]] = xor i32 [[TMP2]], -1
+; CHECK-NEXT:    [[X:%.*]] = sub i32 [[TMP2]], [[A]]
+; CHECK-NEXT:    call void @use32(i32 [[L1]])
+; CHECK-NEXT:    call void @use32(i32 [[NOT]])
+; CHECK-NEXT:    ret i32 [[X]]
+;
+  %not = xor i32 %A, -1
+  %B = xor i32 %Bi, -1
+  %l0 = icmp ult i32 %B, %not
+  %l1 = select i1 %l0, i32 %B, i32 %not
+  %x = sub i32 %not, %l1
+  call void @use32(i32 %l1)
+  call void @use32(i32 %not)
+  ret i32 %x
+}
+
+define i8 @umin_not_sub(i8 %x, i8 %y) {
+; CHECK-LABEL: @umin_not_sub(
+; CHECK-NEXT:    [[NX:%.*]] = xor i8 [[X:%.*]], -1
+; CHECK-NEXT:    [[NY:%.*]] = xor i8 [[Y:%.*]], -1
+; CHECK-NEXT:    [[CMPXY:%.*]] = icmp ult i8 [[NX]], [[NY]]
+; CHECK-NEXT:    [[MINXY:%.*]] = select i1 [[CMPXY]], i8 [[NX]], i8 [[NY]]
+; CHECK-NEXT:    [[SUBX:%.*]] = sub i8 [[NX]], [[MINXY]]
+; CHECK-NEXT:    [[SUBY:%.*]] = sub i8 [[NY]], [[MINXY]]
+; CHECK-NEXT:    call void @use8(i8 [[SUBX]])
+; CHECK-NEXT:    call void @use8(i8 [[SUBY]])
+; CHECK-NEXT:    ret i8 [[MINXY]]
+;
+  %nx = xor i8 %x, -1
+  %ny = xor i8 %y, -1
+  %cmpxy = icmp ult i8 %nx, %ny
+  %minxy = select i1 %cmpxy, i8 %nx, i8 %ny
+  %subx = sub i8 %nx, %minxy
+  %suby = sub i8 %ny, %minxy
+  call void @use8(i8 %subx)
+  call void @use8(i8 %suby)
+  ret i8 %minxy
+}
+
+define i8 @umin_not_sub_rev(i8 %x, i8 %y) {
+; CHECK-LABEL: @umin_not_sub_rev(
+; CHECK-NEXT:    [[NX:%.*]] = xor i8 [[X:%.*]], -1
+; CHECK-NEXT:    [[NY:%.*]] = xor i8 [[Y:%.*]], -1
+; CHECK-NEXT:    [[CMPXY:%.*]] = icmp ult i8 [[NX]], [[NY]]
+; CHECK-NEXT:    [[MINXY:%.*]] = select i1 [[CMPXY]], i8 [[NX]], i8 [[NY]]
+; CHECK-NEXT:    [[SUBX:%.*]] = sub i8 [[MINXY]], [[NX]]
+; CHECK-NEXT:    [[SUBY:%.*]] = sub i8 [[MINXY]], [[NY]]
+; CHECK-NEXT:    call void @use8(i8 [[SUBX]])
+; CHECK-NEXT:    call void @use8(i8 [[SUBY]])
+; CHECK-NEXT:    ret i8 [[MINXY]]
+;
+  %nx = xor i8 %x, -1
+  %ny = xor i8 %y, -1
+  %cmpxy = icmp ult i8 %nx, %ny
+  %minxy = select i1 %cmpxy, i8 %nx, i8 %ny
+  %subx = sub i8 %minxy, %nx
+  %suby = sub i8 %minxy, %ny
+  call void @use8(i8 %subx)
+  call void @use8(i8 %suby)
+  ret i8 %minxy
+}
+
+define void @umin3_not_all_ops_extra_uses_invert_subs(i8 %x, i8 %y, i8 %z) {
+; CHECK-LABEL: @umin3_not_all_ops_extra_uses_invert_subs(
+; CHECK-NEXT:    [[XN:%.*]] = xor i8 [[X:%.*]], -1
+; CHECK-NEXT:    [[YN:%.*]] = xor i8 [[Y:%.*]], -1
+; CHECK-NEXT:    [[ZN:%.*]] = xor i8 [[Z:%.*]], -1
+; CHECK-NEXT:    [[CMPXZ:%.*]] = icmp ult i8 [[XN]], [[ZN]]
+; CHECK-NEXT:    [[MINXZ:%.*]] = select i1 [[CMPXZ]], i8 [[XN]], i8 [[ZN]]
+; CHECK-NEXT:    [[CMPXYZ:%.*]] = icmp ult i8 [[MINXZ]], [[YN]]
+; CHECK-NEXT:    [[MINXYZ:%.*]] = select i1 [[CMPXYZ]], i8 [[MINXZ]], i8 [[YN]]
+; CHECK-NEXT:    [[XMIN:%.*]] = sub i8 [[XN]], [[MINXYZ]]
+; CHECK-NEXT:    [[YMIN:%.*]] = sub i8 [[YN]], [[MINXYZ]]
+; CHECK-NEXT:    [[ZMIN:%.*]] = sub i8 [[ZN]], [[MINXYZ]]
+; CHECK-NEXT:    call void @use8(i8 [[MINXYZ]])
+; CHECK-NEXT:    call void @use8(i8 [[XMIN]])
+; CHECK-NEXT:    call void @use8(i8 [[YMIN]])
+; CHECK-NEXT:    call void @use8(i8 [[ZMIN]])
+; CHECK-NEXT:    ret void
+;
+  %xn = xor i8 %x, -1
+  %yn = xor i8 %y, -1
+  %zn = xor i8 %z, -1
+  %cmpxz = icmp ult i8 %xn, %zn
+  %minxz = select i1 %cmpxz, i8 %xn, i8 %zn
+  %cmpxyz = icmp ult i8 %minxz, %yn
+  %minxyz = select i1 %cmpxyz, i8 %minxz, i8 %yn
+  %xmin = sub i8 %xn, %minxyz
+  %ymin = sub i8 %yn, %minxyz
+  %zmin = sub i8 %zn, %minxyz
+  call void @use8(i8 %minxyz)
+  call void @use8(i8 %xmin)
+  call void @use8(i8 %ymin)
+  call void @use8(i8 %zmin)
+  ret void
+}
+
+declare void @use8(i8)
+declare void @use32(i32 %u)