[NFC][InstCombine] Add test coverage for @llvm.uadd.sat canonicalization

The non-strict variants are already handled because they are canonicalized
to strict variants by swapping hands in both the select and icmp,
and the fold simply considers that strictness is irrelevant here.

But that isn't actually true for the last pattern, as PR48390 reports.

diff --git a/llvm/test/Transforms/InstCombine/saturating-add-sub.ll b/llvm/test/Transforms/InstCombine/saturating-add-sub.ll
index 4585bc2..c5504cc 100644 (file)
--- a/llvm/test/Transforms/InstCombine/saturating-add-sub.ll
+++ b/llvm/test/Transforms/InstCombine/saturating-add-sub.ll
@@ -1208,6 +1208,17 @@ define i32 @uadd_sat(i32 %x, i32 %y) {
   %r = select i1 %c, i32 -1, i32 %a
   ret i32 %r
 }
+define i32 @uadd_sat_nonstrict(i32 %x, i32 %y) {
+; CHECK-LABEL: @uadd_sat_nonstrict(
+; CHECK-NEXT:    [[TMP1:%.*]] = call i32 @llvm.uadd.sat.i32(i32 [[X:%.*]], i32 [[Y:%.*]])
+; CHECK-NEXT:    ret i32 [[TMP1]]
+;
+  %notx = xor i32 %x, -1
+  %a = add i32 %y, %x
+  %c = icmp ule i32 %notx, %y
+  %r = select i1 %c, i32 -1, i32 %a
+  ret i32 %r
+}
 
 define i32 @uadd_sat_commute_add(i32 %xp, i32 %y) {
 ; CHECK-LABEL: @uadd_sat_commute_add(
@@ -1236,6 +1247,19 @@ define i32 @uadd_sat_ugt(i32 %x, i32 %yp) {
   %r = select i1 %c, i32 -1, i32 %a
   ret i32 %r
 }
+define i32 @uadd_sat_uge(i32 %x, i32 %yp) {
+; CHECK-LABEL: @uadd_sat_uge(
+; CHECK-NEXT:    [[Y:%.*]] = sdiv i32 [[YP:%.*]], 2442
+; CHECK-NEXT:    [[TMP1:%.*]] = call i32 @llvm.uadd.sat.i32(i32 [[X:%.*]], i32 [[Y]])
+; CHECK-NEXT:    ret i32 [[TMP1]]
+;
+  %y = sdiv i32 %yp, 2442 ; thwart complexity-based-canonicalization
+  %notx = xor i32 %x, -1
+  %a = add i32 %y, %x
+  %c = icmp uge i32 %y, %notx
+  %r = select i1 %c, i32 -1, i32 %a
+  ret i32 %r
+}
 
 define <2 x i32> @uadd_sat_ugt_commute_add(<2 x i32> %xp, <2 x i32> %yp) {
 ; CHECK-LABEL: @uadd_sat_ugt_commute_add(
@@ -1267,6 +1291,20 @@ define i32 @uadd_sat_commute_select(i32 %x, i32 %yp) {
   ret i32 %r
 }
 
+define i32 @uadd_sat_commute_select_nonstrict(i32 %x, i32 %yp) {
+; CHECK-LABEL: @uadd_sat_commute_select_nonstrict(
+; CHECK-NEXT:    [[Y:%.*]] = sdiv i32 [[YP:%.*]], 2442
+; CHECK-NEXT:    [[TMP1:%.*]] = call i32 @llvm.uadd.sat.i32(i32 [[X:%.*]], i32 [[Y]])
+; CHECK-NEXT:    ret i32 [[TMP1]]
+;
+  %y = sdiv i32 %yp, 2442 ; thwart complexity-based-canonicalization
+  %notx = xor i32 %x, -1
+  %a = add i32 %y, %x
+  %c = icmp ule i32 %y, %notx
+  %r = select i1 %c, i32 %a, i32 -1
+  ret i32 %r
+}
+
 define i32 @uadd_sat_commute_select_commute_add(i32 %xp, i32 %yp) {
 ; CHECK-LABEL: @uadd_sat_commute_select_commute_add(
 ; CHECK-NEXT:    [[X:%.*]] = urem i32 42, [[XP:%.*]]
@@ -1354,6 +1392,19 @@ define i32 @uadd_sat_not(i32 %x, i32 %y) {
   ret i32 %r
 }
 
+define i32 @uadd_sat_not_nonstrict(i32 %x, i32 %y) {
+; CHECK-LABEL: @uadd_sat_not_nonstrict(
+; CHECK-NEXT:    [[NOTX:%.*]] = xor i32 [[X:%.*]], -1
+; CHECK-NEXT:    [[TMP1:%.*]] = call i32 @llvm.uadd.sat.i32(i32 [[NOTX]], i32 [[Y:%.*]])
+; CHECK-NEXT:    ret i32 [[TMP1]]
+;
+  %notx = xor i32 %x, -1
+  %a = add i32 %notx, %y
+  %c = icmp ule i32 %x, %y
+  %r = select i1 %c, i32 -1, i32 %a
+  ret i32 %r
+}
+
 define i32 @uadd_sat_not_commute_add(i32 %xp, i32 %yp) {
 ; CHECK-LABEL: @uadd_sat_not_commute_add(
 ; CHECK-NEXT:    [[X:%.*]] = srem i32 42, [[XP:%.*]]
@@ -1384,6 +1435,19 @@ define i32 @uadd_sat_not_ugt(i32 %x, i32 %y) {
   ret i32 %r
 }
 
+define i32 @uadd_sat_not_uge(i32 %x, i32 %y) {
+; CHECK-LABEL: @uadd_sat_not_uge(
+; CHECK-NEXT:    [[NOTX:%.*]] = xor i32 [[X:%.*]], -1
+; CHECK-NEXT:    [[TMP1:%.*]] = call i32 @llvm.uadd.sat.i32(i32 [[NOTX]], i32 [[Y:%.*]])
+; CHECK-NEXT:    ret i32 [[TMP1]]
+;
+  %notx = xor i32 %x, -1
+  %a = add i32 %notx, %y
+  %c = icmp uge i32 %y, %x
+  %r = select i1 %c, i32 -1, i32 %a
+  ret i32 %r
+}
+
 define <2 x i32> @uadd_sat_not_ugt_commute_add(<2 x i32> %x, <2 x i32> %yp) {
 ; CHECK-LABEL: @uadd_sat_not_ugt_commute_add(
 ; CHECK-NEXT:    [[Y:%.*]] = sdiv <2 x i32> [[YP:%.*]], <i32 2442, i32 4242>
@@ -1412,6 +1476,19 @@ define i32 @uadd_sat_not_commute_select(i32 %x, i32 %y) {
   ret i32 %r
 }
 
+define i32 @uadd_sat_not_commute_select_nonstrict(i32 %x, i32 %y) {
+; CHECK-LABEL: @uadd_sat_not_commute_select_nonstrict(
+; CHECK-NEXT:    [[NOTX:%.*]] = xor i32 [[X:%.*]], -1
+; CHECK-NEXT:    [[TMP1:%.*]] = call i32 @llvm.uadd.sat.i32(i32 [[NOTX]], i32 [[Y:%.*]])
+; CHECK-NEXT:    ret i32 [[TMP1]]
+;
+  %notx = xor i32 %x, -1
+  %a = add i32 %notx, %y
+  %c = icmp ule i32 %y, %x
+  %r = select i1 %c, i32 %a, i32 -1
+  ret i32 %r
+}
+
 define i32 @uadd_sat_not_commute_select_commute_add(i32 %x, i32 %yp) {
 ; CHECK-LABEL: @uadd_sat_not_commute_select_commute_add(
 ; CHECK-NEXT:    [[Y:%.*]] = sdiv i32 42, [[YP:%.*]]
@@ -1457,6 +1534,19 @@ define i32 @uadd_sat_not_commute_select_ugt_commute_add(i32 %x, i32 %y) {
   ret i32 %r
 }
 
+define i32 @uadd_sat_not_commute_select_uge_commute_add(i32 %x, i32 %y) {
+; CHECK-LABEL: @uadd_sat_not_commute_select_uge_commute_add(
+; CHECK-NEXT:    [[NOTX:%.*]] = xor i32 [[X:%.*]], -1
+; CHECK-NEXT:    [[TMP1:%.*]] = call i32 @llvm.uadd.sat.i32(i32 [[NOTX]], i32 [[Y:%.*]])
+; CHECK-NEXT:    ret i32 [[TMP1]]
+;
+  %notx = xor i32 %x, -1
+  %a = add i32 %notx, %y
+  %c = icmp uge i32 %x, %y
+  %r = select i1 %c, i32 %a, i32 -1
+  ret i32 %r
+}
+
 define i32 @uadd_sat_constant(i32 %x) {
 ; CHECK-LABEL: @uadd_sat_constant(
 ; CHECK-NEXT:    [[A:%.*]] = add i32 [[X:%.*]], 42
@@ -1697,3 +1787,91 @@ define i32 @unsigned_sat_constant_using_min_wrong_constant(i32 %x) {
   %r = add i32 %s, -42
   ret i32 %r
 }
+
+define i32 @uadd_sat_via_add(i32 %x, i32 %y) {
+; CHECK-LABEL: @uadd_sat_via_add(
+; CHECK-NEXT:    [[TMP1:%.*]] = call i32 @llvm.uadd.sat.i32(i32 [[Y:%.*]], i32 [[X:%.*]])
+; CHECK-NEXT:    ret i32 [[TMP1]]
+;
+  %a = add i32 %x, %y
+  %c = icmp ult i32 %a, %y
+  %r = select i1 %c, i32 -1, i32 %a
+  ret i32 %r
+}
+
+define i32 @uadd_sat_via_add_nonstrict(i32 %x, i32 %y) {
+; CHECK-LABEL: @uadd_sat_via_add_nonstrict(
+; CHECK-NEXT:    [[TMP1:%.*]] = call i32 @llvm.uadd.sat.i32(i32 [[Y:%.*]], i32 [[X:%.*]])
+; CHECK-NEXT:    ret i32 [[TMP1]]
+;
+  %a = add i32 %x, %y
+  %c = icmp ule i32 %a, %y
+  %r = select i1 %c, i32 -1, i32 %a
+  ret i32 %r
+}
+
+define i32 @uadd_sat_via_add_swapped_select(i32 %x, i32 %y) {
+; CHECK-LABEL: @uadd_sat_via_add_swapped_select(
+; CHECK-NEXT:    [[TMP1:%.*]] = call i32 @llvm.uadd.sat.i32(i32 [[Y:%.*]], i32 [[X:%.*]])
+; CHECK-NEXT:    ret i32 [[TMP1]]
+;
+  %a = add i32 %x, %y
+  %c = icmp uge i32 %a, %y
+  %r = select i1 %c, i32 %a, i32 -1
+  ret i32 %r
+}
+
+define i32 @uadd_sat_via_add_swapped_select_strict(i32 %x, i32 %y) {
+; CHECK-LABEL: @uadd_sat_via_add_swapped_select_strict(
+; CHECK-NEXT:    [[TMP1:%.*]] = call i32 @llvm.uadd.sat.i32(i32 [[Y:%.*]], i32 [[X:%.*]])
+; CHECK-NEXT:    ret i32 [[TMP1]]
+;
+  %a = add i32 %x, %y
+  %c = icmp ugt i32 %a, %y
+  %r = select i1 %c, i32 %a, i32 -1
+  ret i32 %r
+}
+
+define i32 @uadd_sat_via_add_swapped_cmp(i32 %x, i32 %y) {
+; CHECK-LABEL: @uadd_sat_via_add_swapped_cmp(
+; CHECK-NEXT:    [[TMP1:%.*]] = call i32 @llvm.uadd.sat.i32(i32 [[Y:%.*]], i32 [[X:%.*]])
+; CHECK-NEXT:    ret i32 [[TMP1]]
+;
+  %a = add i32 %x, %y
+  %c = icmp ugt i32 %y, %a
+  %r = select i1 %c, i32 -1, i32 %a
+  ret i32 %r
+}
+
+define i32 @uadd_sat_via_add_swapped_cmp_nonstrict(i32 %x, i32 %y) {
+; CHECK-LABEL: @uadd_sat_via_add_swapped_cmp_nonstrict(
+; CHECK-NEXT:    [[TMP1:%.*]] = call i32 @llvm.uadd.sat.i32(i32 [[Y:%.*]], i32 [[X:%.*]])
+; CHECK-NEXT:    ret i32 [[TMP1]]
+;
+  %a = add i32 %x, %y
+  %c = icmp uge i32 %y, %a
+  %r = select i1 %c, i32 -1, i32 %a
+  ret i32 %r
+}
+
+define i32 @uadd_sat_via_add_swapped_cmp_nonstric(i32 %x, i32 %y) {
+; CHECK-LABEL: @uadd_sat_via_add_swapped_cmp_nonstric(
+; CHECK-NEXT:    [[TMP1:%.*]] = call i32 @llvm.uadd.sat.i32(i32 [[Y:%.*]], i32 [[X:%.*]])
+; CHECK-NEXT:    ret i32 [[TMP1]]
+;
+  %a = add i32 %x, %y
+  %c = icmp ule i32 %y, %a
+  %r = select i1 %c, i32 %a, i32 -1
+  ret i32 %r
+}
+
+define i32 @uadd_sat_via_add_swapped_cmp_select_nonstrict(i32 %x, i32 %y) {
+; CHECK-LABEL: @uadd_sat_via_add_swapped_cmp_select_nonstrict(
+; CHECK-NEXT:    [[TMP1:%.*]] = call i32 @llvm.uadd.sat.i32(i32 [[Y:%.*]], i32 [[X:%.*]])
+; CHECK-NEXT:    ret i32 [[TMP1]]
+;
+  %a = add i32 %x, %y
+  %c = icmp ult i32 %y, %a
+  %r = select i1 %c, i32 %a, i32 -1
+  ret i32 %r
+}