Index: llvm/trunk/test/Transforms/InstCombine/sub-ashr-and-to-icmp-select.ll
===================================================================
--- llvm/trunk/test/Transforms/InstCombine/sub-ashr-and-to-icmp-select.ll
+++ llvm/trunk/test/Transforms/InstCombine/sub-ashr-and-to-icmp-select.ll
@@ -0,0 +1,223 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt -instcombine %s -S -o - | FileCheck %s
+
+; Clamp negative to zero:
+; E.g., clamp0 implemented in a shifty way, could be optimized as v > 0 ? v : 0, where sub hasNoSignedWrap.
+; int32 clamp0(int32 v) {
+;   return ((-(v) >> 31) & (v));
+; }
+;
+
+; Scalar Types
+
+define i8 @sub_ashr_and_i8(i8 %x, i8 %y) {
+; CHECK-LABEL: @sub_ashr_and_i8(
+; CHECK-NEXT:    [[SUB:%.*]] = sub nsw i8 [[Y:%.*]], [[X:%.*]]
+; CHECK-NEXT:    [[SHR:%.*]] = ashr i8 [[SUB]], 7
+; CHECK-NEXT:    [[AND:%.*]] = and i8 [[SHR]], [[X]]
+; CHECK-NEXT:    ret i8 [[AND]]
+;
+  %sub = sub nsw i8 %y, %x
+  %shr = ashr i8 %sub, 7
+  %and = and i8 %shr, %x
+  ret i8 %and
+}
+
+define i16 @sub_ashr_and_i16(i16 %x, i16 %y) {
+; CHECK-LABEL: @sub_ashr_and_i16(
+; CHECK-NEXT:    [[SUB:%.*]] = sub nsw i16 [[Y:%.*]], [[X:%.*]]
+; CHECK-NEXT:    [[SHR:%.*]] = ashr i16 [[SUB]], 15
+; CHECK-NEXT:    [[AND:%.*]] = and i16 [[SHR]], [[X]]
+; CHECK-NEXT:    ret i16 [[AND]]
+;
+
+  %sub = sub nsw i16 %y, %x
+  %shr = ashr i16 %sub, 15
+  %and = and i16 %shr, %x
+  ret i16 %and
+}
+
+define i32 @sub_ashr_and_i32(i32 %x, i32 %y) {
+; CHECK-LABEL: @sub_ashr_and_i32(
+; CHECK-NEXT:    [[SUB:%.*]] = sub nsw i32 [[Y:%.*]], [[X:%.*]]
+; CHECK-NEXT:    [[SHR:%.*]] = ashr i32 [[SUB]], 31
+; CHECK-NEXT:    [[AND:%.*]] = and i32 [[SHR]], [[X]]
+; CHECK-NEXT:    ret i32 [[AND]]
+;
+  %sub = sub nsw i32 %y, %x
+  %shr = ashr i32 %sub, 31
+  %and = and i32 %shr, %x
+  ret i32 %and
+}
+
+define i64 @sub_ashr_and_i64(i64 %x, i64 %y) {
+; CHECK-LABEL: @sub_ashr_and_i64(
+; CHECK-NEXT:    [[SUB:%.*]] = sub nsw i64 [[Y:%.*]], [[X:%.*]]
+; CHECK-NEXT:    [[SHR:%.*]] = ashr i64 [[SUB]], 63
+; CHECK-NEXT:    [[AND:%.*]] = and i64 [[SHR]], [[X]]
+; CHECK-NEXT:    ret i64 [[AND]]
+;
+  %sub = sub nsw i64 %y, %x
+  %shr = ashr i64 %sub, 63
+  %and = and i64 %shr, %x
+  ret i64 %and
+}
+
+; nuw nsw
+
+define i32 @sub_ashr_and_i32_nuw_nsw(i32 %x, i32 %y) {
+; CHECK-LABEL: @sub_ashr_and_i32_nuw_nsw(
+; CHECK-NEXT:    [[SUB:%.*]] = sub nuw nsw i32 [[Y:%.*]], [[X:%.*]]
+; CHECK-NEXT:    [[SHR:%.*]] = ashr i32 [[SUB]], 31
+; CHECK-NEXT:    [[AND:%.*]] = and i32 [[SHR]], [[X]]
+; CHECK-NEXT:    ret i32 [[AND]]
+;
+  %sub = sub nuw nsw i32 %y, %x
+  %shr = ashr i32 %sub, 31
+  %and = and i32 %shr, %x
+  ret i32 %and
+}
+
+; Commute
+
+define i32 @sub_ashr_and_i32_commute(i32 %x, i32 %y) {
+; CHECK-LABEL: @sub_ashr_and_i32_commute(
+; CHECK-NEXT:    [[SUB:%.*]] = sub nsw i32 [[Y:%.*]], [[X:%.*]]
+; CHECK-NEXT:    [[SHR:%.*]] = ashr i32 [[SUB]], 31
+; CHECK-NEXT:    [[AND:%.*]] = and i32 [[SHR]], [[X]]
+; CHECK-NEXT:    ret i32 [[AND]]
+;
+  %sub = sub nsw i32 %y, %x
+  %shr = ashr i32 %sub, 31
+  %and = and i32 %x, %shr  ; commute %x and %shr
+  ret i32 %and
+}
+
+; Vector Types
+
+define <4 x i32> @sub_ashr_and_i32_vec(<4 x i32> %x, <4 x i32> %y) {
+; CHECK-LABEL: @sub_ashr_and_i32_vec(
+; CHECK-NEXT:    [[SUB:%.*]] = sub nsw <4 x i32> [[Y:%.*]], [[X:%.*]]
+; CHECK-NEXT:    [[SHR:%.*]] = ashr <4 x i32> [[SUB]], <i32 31, i32 31, i32 31, i32 31>
+; CHECK-NEXT:    [[AND:%.*]] = and <4 x i32> [[SHR]], [[X]]
+; CHECK-NEXT:    ret <4 x i32> [[AND]]
+;
+  %sub = sub nsw <4 x i32> %y, %x
+  %shr = ashr <4 x i32> %sub, <i32 31, i32 31, i32 31, i32 31>
+  %and = and <4 x i32> %shr, %x
+  ret <4 x i32> %and
+}
+
+define <4 x i32> @sub_ashr_and_i32_vec_nuw_nsw(<4 x i32> %x, <4 x i32> %y) {
+; CHECK-LABEL: @sub_ashr_and_i32_vec_nuw_nsw(
+; CHECK-NEXT:    [[SUB:%.*]] = sub nuw nsw <4 x i32> [[Y:%.*]], [[X:%.*]]
+; CHECK-NEXT:    [[SHR:%.*]] = ashr <4 x i32> [[SUB]], <i32 31, i32 31, i32 31, i32 31>
+; CHECK-NEXT:    [[AND:%.*]] = and <4 x i32> [[SHR]], [[X]]
+; CHECK-NEXT:    ret <4 x i32> [[AND]]
+;
+  %sub = sub nuw nsw <4 x i32> %y, %x
+  %shr = ashr <4 x i32> %sub, <i32 31, i32 31, i32 31, i32 31>
+  %and = and <4 x i32> %shr, %x
+  ret <4 x i32> %and
+}
+
+define <4 x i32> @sub_ashr_and_i32_vec_commute(<4 x i32> %x, <4 x i32> %y) {
+; CHECK-LABEL: @sub_ashr_and_i32_vec_commute(
+; CHECK-NEXT:    [[SUB:%.*]] = sub nsw <4 x i32> [[Y:%.*]], [[X:%.*]]
+; CHECK-NEXT:    [[SHR:%.*]] = ashr <4 x i32> [[SUB]], <i32 31, i32 31, i32 31, i32 31>
+; CHECK-NEXT:    [[AND:%.*]] = and <4 x i32> [[SHR]], [[X]]
+; CHECK-NEXT:    ret <4 x i32> [[AND]]
+;
+  %sub = sub nsw <4 x i32> %y, %x
+  %shr = ashr <4 x i32> %sub, <i32 31, i32 31, i32 31, i32 31>
+  %and = and <4 x i32> %x, %shr  ; commute %x and %shr
+  ret <4 x i32> %and
+}
+
+; Extra uses
+
+define i32 @sub_ashr_and_i32_extra_use_sub(i32 %x, i32 %y, i32* %p) {
+; CHECK-LABEL: @sub_ashr_and_i32_extra_use_sub(
+; CHECK-NEXT:    [[SUB:%.*]] = sub nsw i32 [[Y:%.*]], [[X:%.*]]
+; CHECK-NEXT:    store i32 [[SUB]], i32* [[P:%.*]], align 4
+; CHECK-NEXT:    [[SHR:%.*]] = ashr i32 [[SUB]], 31
+; CHECK-NEXT:    [[AND:%.*]] = and i32 [[SHR]], [[X]]
+; CHECK-NEXT:    ret i32 [[AND]]
+;
+  %sub = sub nsw i32 %y, %x
+  store i32 %sub, i32* %p
+  %shr = ashr i32 %sub, 31
+  %and = and i32 %shr, %x
+  ret i32 %and
+}
+
+define i32 @sub_ashr_and_i32_extra_use_and(i32 %x, i32 %y, i32* %p) {
+; CHECK-LABEL: @sub_ashr_and_i32_extra_use_and(
+; CHECK-NEXT:    [[SUB:%.*]] = sub nsw i32 [[Y:%.*]], [[X:%.*]]
+; CHECK-NEXT:    [[SHR:%.*]] = ashr i32 [[SUB]], 31
+; CHECK-NEXT:    [[AND:%.*]] = and i32 [[SHR]], [[X]]
+; CHECK-NEXT:    store i32 [[AND]], i32* [[P:%.*]], align 4
+; CHECK-NEXT:    ret i32 [[AND]]
+;
+  %sub = sub nsw i32 %y, %x
+  %shr = ashr i32 %sub, 31
+  %and = and i32 %shr, %x
+  store i32 %and, i32* %p
+  ret i32 %and
+}
+
+; Negative Tests
+
+define i32 @sub_ashr_and_i32_extra_use_ashr(i32 %x, i32 %y, i32* %p) {
+; CHECK-LABEL: @sub_ashr_and_i32_extra_use_ashr(
+; CHECK-NEXT:    [[SUB:%.*]] = sub nsw i32 [[Y:%.*]], [[X:%.*]]
+; CHECK-NEXT:    [[SHR:%.*]] = ashr i32 [[SUB]], 31
+; CHECK-NEXT:    store i32 [[SHR]], i32* [[P:%.*]], align 4
+; CHECK-NEXT:    [[AND:%.*]] = and i32 [[SHR]], [[X]]
+; CHECK-NEXT:    ret i32 [[AND]]
+;
+  %sub = sub nsw i32 %y, %x
+  %shr = ashr i32 %sub, 31
+  store i32 %shr, i32* %p
+  %and = and i32 %shr, %x
+  ret i32 %and
+}
+
+define i32 @sub_ashr_and_i32_no_nuw_nsw(i32 %x, i32 %y) {
+; CHECK-LABEL: @sub_ashr_and_i32_no_nuw_nsw(
+; CHECK-NEXT:    [[SUB:%.*]] = sub i32 [[Y:%.*]], [[X:%.*]]
+; CHECK-NEXT:    [[SHR:%.*]] = ashr i32 [[SUB]], 7
+; CHECK-NEXT:    [[AND:%.*]] = and i32 [[SHR]], [[X]]
+; CHECK-NEXT:    ret i32 [[AND]]
+;
+  %sub = sub i32 %y, %x
+  %shr = ashr i32 %sub, 7
+  %and = and i32 %shr, %x
+  ret i32 %and
+}
+
+define <4 x i32> @sub_ashr_and_i32_vec_undef(<4 x i32> %x, <4 x i32> %y) {
+; CHECK-LABEL: @sub_ashr_and_i32_vec_undef(
+; CHECK-NEXT:    [[SUB:%.*]] = sub nsw <4 x i32> [[Y:%.*]], [[X:%.*]]
+; CHECK-NEXT:    [[SHR:%.*]] = ashr <4 x i32> [[SUB]], <i32 31, i32 31, i32 31, i32 undef>
+; CHECK-NEXT:    [[AND:%.*]] = and <4 x i32> [[SHR]], [[X]]
+; CHECK-NEXT:    ret <4 x i32> [[AND]]
+;
+  %sub = sub nsw <4 x i32> %y, %x
+  %shr = ashr <4 x i32> %sub, <i32 31, i32 31, i32 31, i32 undef>
+  %and = and <4 x i32> %shr, %x
+  ret <4 x i32> %and
+}
+
+define i32 @sub_ashr_and_i32_shift_wrong_bit(i32 %x, i32 %y) {
+; CHECK-LABEL: @sub_ashr_and_i32_shift_wrong_bit(
+; CHECK-NEXT:    [[SUB:%.*]] = sub nsw i32 [[Y:%.*]], [[X:%.*]]
+; CHECK-NEXT:    [[SHR:%.*]] = ashr i32 [[SUB]], 15
+; CHECK-NEXT:    [[AND:%.*]] = and i32 [[SHR]], [[X]]
+; CHECK-NEXT:    ret i32 [[AND]]
+;
+  %sub = sub nsw i32 %y, %x
+  %shr = ashr i32 %sub, 15
+  %and = and i32 %shr, %x
+  ret i32 %and
+}
Index: llvm/trunk/test/Transforms/InstCombine/sub-ashr-or-to-icmp-select.ll
===================================================================
--- llvm/trunk/test/Transforms/InstCombine/sub-ashr-or-to-icmp-select.ll
+++ llvm/trunk/test/Transforms/InstCombine/sub-ashr-or-to-icmp-select.ll
@@ -0,0 +1,250 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt -instcombine %s -S -o - | FileCheck %s
+
+; Clamp positive to allOnes:
+; E.g., clamp255 implemented in a shifty way, could be optimized as v > 255 ? 255 : v, where sub hasNoSignedWrap.
+; int32 clamp255(int32 v) {
+;   return (((255 - (v)) >> 31) | (v)) & 255;
+; }
+;
+
+; Scalar Types
+
+define i32 @clamp255_i32(i32 %x) {
+; CHECK-LABEL: @clamp255_i32(
+; CHECK-NEXT:    [[SUB:%.*]] = sub nsw i32 255, [[X:%.*]]
+; CHECK-NEXT:    [[SHR:%.*]] = ashr i32 [[SUB]], 31
+; CHECK-NEXT:    [[OR:%.*]] = or i32 [[SHR]], [[X]]
+; CHECK-NEXT:    [[AND:%.*]] = and i32 [[OR]], 255
+; CHECK-NEXT:    ret i32 [[AND]]
+;
+  %sub = sub nsw i32 255, %x
+  %shr = ashr i32 %sub, 31
+  %or = or i32 %shr, %x
+  %and = and i32 %or, 255
+  ret i32 %and
+}
+
+define i8 @sub_ashr_or_i8(i8 %x, i8 %y) {
+; CHECK-LABEL: @sub_ashr_or_i8(
+; CHECK-NEXT:    [[SUB:%.*]] = sub nsw i8 [[Y:%.*]], [[X:%.*]]
+; CHECK-NEXT:    [[SHR:%.*]] = ashr i8 [[SUB]], 7
+; CHECK-NEXT:    [[OR:%.*]] = or i8 [[SHR]], [[X]]
+; CHECK-NEXT:    ret i8 [[OR]]
+;
+  %sub = sub nsw i8 %y, %x
+  %shr = ashr i8 %sub, 7
+  %or = or i8 %shr, %x
+  ret i8 %or
+}
+
+define i16 @sub_ashr_or_i16(i16 %x, i16 %y) {
+; CHECK-LABEL: @sub_ashr_or_i16(
+; CHECK-NEXT:    [[SUB:%.*]] = sub nsw i16 [[Y:%.*]], [[X:%.*]]
+; CHECK-NEXT:    [[SHR:%.*]] = ashr i16 [[SUB]], 15
+; CHECK-NEXT:    [[OR:%.*]] = or i16 [[SHR]], [[X]]
+; CHECK-NEXT:    ret i16 [[OR]]
+;
+  %sub = sub nsw i16 %y, %x
+  %shr = ashr i16 %sub, 15
+  %or = or i16 %shr, %x
+  ret i16 %or
+}
+
+define i32 @sub_ashr_or_i32(i32 %x, i32 %y) {
+; CHECK-LABEL: @sub_ashr_or_i32(
+; CHECK-NEXT:    [[SUB:%.*]] = sub nsw i32 [[Y:%.*]], [[X:%.*]]
+; CHECK-NEXT:    [[SHR:%.*]] = ashr i32 [[SUB]], 31
+; CHECK-NEXT:    [[OR:%.*]] = or i32 [[SHR]], [[X]]
+; CHECK-NEXT:    ret i32 [[OR]]
+;
+  %sub = sub nsw i32 %y, %x
+  %shr = ashr i32 %sub, 31
+  %or = or i32 %shr, %x
+  ret i32 %or
+}
+
+define i64 @sub_ashr_or_i64(i64 %x, i64 %y) {
+; CHECK-LABEL: @sub_ashr_or_i64(
+; CHECK-NEXT:    [[SUB:%.*]] = sub nsw i64 [[Y:%.*]], [[X:%.*]]
+; CHECK-NEXT:    [[SHR:%.*]] = ashr i64 [[SUB]], 63
+; CHECK-NEXT:    [[OR:%.*]] = or i64 [[SHR]], [[X]]
+; CHECK-NEXT:    ret i64 [[OR]]
+;
+  %sub = sub nsw i64 %y, %x
+  %shr = ashr i64 %sub, 63
+  %or = or i64 %shr, %x
+  ret i64 %or
+}
+
+; nuw nsw
+
+define i32 @sub_ashr_or_i32_nuw_nsw(i32 %x, i32 %y) {
+; CHECK-LABEL: @sub_ashr_or_i32_nuw_nsw(
+; CHECK-NEXT:    [[SUB:%.*]] = sub nuw nsw i32 [[Y:%.*]], [[X:%.*]]
+; CHECK-NEXT:    [[SHR:%.*]] = ashr i32 [[SUB]], 31
+; CHECK-NEXT:    [[OR:%.*]] = or i32 [[SHR]], [[X]]
+; CHECK-NEXT:    ret i32 [[OR]]
+;
+  %sub = sub nuw nsw i32 %y, %x
+  %shr = ashr i32 %sub, 31
+  %or = or i32 %shr, %x
+  ret i32 %or
+}
+
+; Commute
+
+define i32 @sub_ashr_or_i32_commute(i32 %x, i32 %y) {
+; CHECK-LABEL: @sub_ashr_or_i32_commute(
+; CHECK-NEXT:    [[SUB:%.*]] = sub nsw i32 [[Y:%.*]], [[X:%.*]]
+; CHECK-NEXT:    [[SHR:%.*]] = ashr i32 [[SUB]], 31
+; CHECK-NEXT:    [[OR:%.*]] = or i32 [[SHR]], [[X]]
+; CHECK-NEXT:    ret i32 [[OR]]
+;
+  %sub = sub nsw i32 %y, %x
+  %shr = ashr i32 %sub, 31
+  %or = or i32 %x, %shr  ; commute %shr and %x
+  ret i32 %or
+}
+
+; Vector Types
+
+define <4 x i32> @sub_ashr_or_i32_vec(<4 x i32> %x, <4 x i32> %y) {
+; CHECK-LABEL: @sub_ashr_or_i32_vec(
+; CHECK-NEXT:    [[SUB:%.*]] = sub nsw <4 x i32> [[Y:%.*]], [[X:%.*]]
+; CHECK-NEXT:    [[SHR:%.*]] = ashr <4 x i32> [[SUB]], <i32 31, i32 31, i32 31, i32 31>
+; CHECK-NEXT:    [[OR:%.*]] = or <4 x i32> [[SHR]], [[X]]
+; CHECK-NEXT:    ret <4 x i32> [[OR]]
+;
+  %sub = sub nsw <4 x i32> %y, %x
+  %shr = ashr <4 x i32> %sub, <i32 31, i32 31, i32 31, i32 31>
+  %or = or <4 x i32> %shr, %x
+  ret <4 x i32> %or
+}
+
+define <4 x i32> @sub_ashr_or_i32_vec_nuw_nsw(<4 x i32> %x, <4 x i32> %y) {
+; CHECK-LABEL: @sub_ashr_or_i32_vec_nuw_nsw(
+; CHECK-NEXT:    [[SUB:%.*]] = sub nuw nsw <4 x i32> [[Y:%.*]], [[X:%.*]]
+; CHECK-NEXT:    [[SHR:%.*]] = ashr <4 x i32> [[SUB]], <i32 31, i32 31, i32 31, i32 31>
+; CHECK-NEXT:    [[OR:%.*]] = or <4 x i32> [[SHR]], [[X]]
+; CHECK-NEXT:    ret <4 x i32> [[OR]]
+;
+  %sub = sub nuw nsw <4 x i32> %y, %x
+  %shr = ashr <4 x i32> %sub, <i32 31, i32 31, i32 31, i32 31>
+  %or = or <4 x i32> %shr, %x
+  ret <4 x i32> %or
+}
+
+define <4 x i32> @sub_ashr_or_i32_vec_commute(<4 x i32> %x, <4 x i32> %y) {
+; CHECK-LABEL: @sub_ashr_or_i32_vec_commute(
+; CHECK-NEXT:    [[SUB:%.*]] = sub nsw <4 x i32> [[Y:%.*]], [[X:%.*]]
+; CHECK-NEXT:    [[SHR:%.*]] = ashr <4 x i32> [[SUB]], <i32 31, i32 31, i32 31, i32 31>
+; CHECK-NEXT:    [[OR:%.*]] = or <4 x i32> [[SHR]], [[X]]
+; CHECK-NEXT:    ret <4 x i32> [[OR]]
+;
+  %sub = sub nsw <4 x i32> %y, %x
+  %shr = ashr <4 x i32> %sub, <i32 31, i32 31, i32 31, i32 31>
+  %or = or <4 x i32> %x, %shr
+  ret <4 x i32> %or
+}
+
+; Extra uses
+
+define i32 @sub_ashr_or_i32_extra_use_sub(i32 %x, i32 %y, i32* %p) {
+; CHECK-LABEL: @sub_ashr_or_i32_extra_use_sub(
+; CHECK-NEXT:    [[SUB:%.*]] = sub nsw i32 [[Y:%.*]], [[X:%.*]]
+; CHECK-NEXT:    store i32 [[SUB]], i32* [[P:%.*]], align 4
+; CHECK-NEXT:    [[SHR:%.*]] = ashr i32 [[SUB]], 31
+; CHECK-NEXT:    [[OR:%.*]] = or i32 [[SHR]], [[X]]
+; CHECK-NEXT:    ret i32 [[OR]]
+;
+  %sub = sub nsw i32 %y, %x
+  store i32 %sub, i32* %p
+  %shr = ashr i32 %sub, 31
+  %or = or i32 %shr, %x
+  ret i32 %or
+}
+
+define i32 @sub_ashr_or_i32_extra_use_or(i32 %x, i32 %y, i32* %p) {
+; CHECK-LABEL: @sub_ashr_or_i32_extra_use_or(
+; CHECK-NEXT:    [[SUB:%.*]] = sub nsw i32 [[Y:%.*]], [[X:%.*]]
+; CHECK-NEXT:    [[SHR:%.*]] = ashr i32 [[SUB]], 31
+; CHECK-NEXT:    [[OR:%.*]] = or i32 [[SHR]], [[X]]
+; CHECK-NEXT:    store i32 [[OR]], i32* [[P:%.*]], align 4
+; CHECK-NEXT:    ret i32 [[OR]]
+;
+  %sub = sub nsw i32 %y, %x
+  %shr = ashr i32 %sub, 31
+  %or = or i32 %shr, %x
+  store i32 %or, i32* %p
+  ret i32 %or
+}
+
+; Negative Tests
+
+define i32 @sub_ashr_or_i32_extra_use_ashr(i32 %x, i32 %y, i32* %p) {
+; CHECK-LABEL: @sub_ashr_or_i32_extra_use_ashr(
+; CHECK-NEXT:    [[SUB:%.*]] = sub nsw i32 [[Y:%.*]], [[X:%.*]]
+; CHECK-NEXT:    [[SHR:%.*]] = ashr i32 [[SUB]], 31
+; CHECK-NEXT:    store i32 [[SHR]], i32* [[P:%.*]], align 4
+; CHECK-NEXT:    [[OR:%.*]] = or i32 [[SHR]], [[X]]
+; CHECK-NEXT:    ret i32 [[OR]]
+;
+  %sub = sub nsw i32 %y, %x
+  %shr = ashr i32 %sub, 31
+  store i32 %shr, i32* %p
+  %or = or i32 %shr, %x
+  ret i32 %or
+}
+
+define i32 @sub_ashr_or_i32_no_nsw_nuw(i32 %x, i32 %y) {
+; CHECK-LABEL: @sub_ashr_or_i32_no_nsw_nuw(
+; CHECK-NEXT:    [[SUB:%.*]] = sub i32 [[Y:%.*]], [[X:%.*]]
+; CHECK-NEXT:    [[SHR:%.*]] = ashr i32 [[SUB]], 31
+; CHECK-NEXT:    [[OR:%.*]] = or i32 [[SHR]], [[X]]
+; CHECK-NEXT:    ret i32 [[OR]]
+;
+  %sub = sub i32 %y, %x
+  %shr = ashr i32 %sub, 31
+  %or = or i32 %shr, %x
+  ret i32 %or
+}
+
+define <4 x i32> @sub_ashr_or_i32_vec_undef1(<4 x i32> %x) {
+; CHECK-LABEL: @sub_ashr_or_i32_vec_undef1(
+; CHECK-NEXT:    [[SUB:%.*]] = sub <4 x i32> <i32 255, i32 255, i32 undef, i32 255>, [[X:%.*]]
+; CHECK-NEXT:    [[SHR:%.*]] = ashr <4 x i32> [[SUB]], <i32 31, i32 31, i32 31, i32 31>
+; CHECK-NEXT:    [[OR:%.*]] = or <4 x i32> [[SHR]], [[X]]
+; CHECK-NEXT:    ret <4 x i32> [[OR]]
+;
+  %sub = sub <4 x i32> <i32 255, i32 255, i32 undef, i32 255>, %x
+  %shr = ashr <4 x i32> %sub, <i32 31, i32 31, i32 31, i32 31>
+  %or = or <4 x i32> %shr, %x
+  ret <4 x i32> %or
+}
+
+define <4 x i32> @sub_ashr_or_i32_vec_undef2(<4 x i32> %x) {
+; CHECK-LABEL: @sub_ashr_or_i32_vec_undef2(
+; CHECK-NEXT:    [[SUB:%.*]] = sub nsw <4 x i32> <i32 255, i32 255, i32 255, i32 255>, [[X:%.*]]
+; CHECK-NEXT:    [[SHR:%.*]] = ashr <4 x i32> [[SUB]], <i32 undef, i32 31, i32 31, i32 31>
+; CHECK-NEXT:    [[OR:%.*]] = or <4 x i32> [[SHR]], [[X]]
+; CHECK-NEXT:    ret <4 x i32> [[OR]]
+;
+  %sub = sub nsw <4 x i32> <i32 255, i32 255, i32 255, i32 255>, %x
+  %shr = ashr <4 x i32> %sub, <i32 undef, i32 31, i32 31, i32 31>
+  %or = or <4 x i32> %shr, %x
+  ret <4 x i32> %or
+}
+
+define i32 @sub_ashr_or_i32_shift_wrong_bit(i32 %x, i32 %y) {
+; CHECK-LABEL: @sub_ashr_or_i32_shift_wrong_bit(
+; CHECK-NEXT:    [[SUB:%.*]] = sub nsw i32 [[Y:%.*]], [[X:%.*]]
+; CHECK-NEXT:    [[SHR:%.*]] = ashr i32 [[SUB]], 11
+; CHECK-NEXT:    [[OR:%.*]] = or i32 [[SHR]], [[X]]
+; CHECK-NEXT:    ret i32 [[OR]]
+;
+  %sub = sub nsw i32 %y, %x
+  %shr = ashr i32 %sub, 11
+  %or = or i32 %shr, %x
+  ret i32 %or
+}