--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/test/Transforms/InstCombine/icmp-shl-nsw.ll	Fri Oct 27 17:07:41 2017 +0900
@@ -0,0 +1,356 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt < %s -instcombine -S | FileCheck %s
+
+; If the (shl x, C) preserved the sign and this is a sign test,
+; compare the LHS operand instead
+
+define i1 @icmp_shl_nsw_sgt(i32 %x) {
+; CHECK-LABEL: @icmp_shl_nsw_sgt(
+; CHECK-NEXT:    [[CMP:%.*]] = icmp sgt i32 %x, 0
+; CHECK-NEXT:    ret i1 [[CMP]]
+;
+  %shl = shl nsw i32 %x, 21
+  %cmp = icmp sgt i32 %shl, 0
+  ret i1 %cmp
+}
+
+define i1 @icmp_shl_nsw_sge0(i32 %x) {
+; CHECK-LABEL: @icmp_shl_nsw_sge0(
+; CHECK-NEXT:    [[CMP:%.*]] = icmp sgt i32 %x, -1
+; CHECK-NEXT:    ret i1 [[CMP]]
+;
+  %shl = shl nsw i32 %x, 21
+  %cmp = icmp sge i32 %shl, 0
+  ret i1 %cmp
+}
+
+define i1 @icmp_shl_nsw_sge1(i32 %x) {
+; CHECK-LABEL: @icmp_shl_nsw_sge1(
+; CHECK-NEXT:    [[CMP:%.*]] = icmp sgt i32 %x, 0
+; CHECK-NEXT:    ret i1 [[CMP]]
+;
+  %shl = shl nsw i32 %x, 21
+  %cmp = icmp sge i32 %shl, 1
+  ret i1 %cmp
+}
+
+define <2 x i1> @icmp_shl_nsw_sge1_vec(<2 x i32> %x) {
+; CHECK-LABEL: @icmp_shl_nsw_sge1_vec(
+; CHECK-NEXT:    [[CMP:%.*]] = icmp sgt <2 x i32> %x, zeroinitializer
+; CHECK-NEXT:    ret <2 x i1> [[CMP]]
+;
+  %shl = shl nsw <2 x i32> %x, <i32 21, i32 21>
+  %cmp = icmp sge <2 x i32> %shl, <i32 1, i32 1>
+  ret <2 x i1> %cmp
+}
+
+; Checks for icmp (eq|ne) (shl x, C), 0
+
+define i1 @icmp_shl_nsw_eq(i32 %x) {
+; CHECK-LABEL: @icmp_shl_nsw_eq(
+; CHECK-NEXT:    [[CMP:%.*]] = icmp eq i32 %x, 0
+; CHECK-NEXT:    ret i1 [[CMP]]
+;
+  %mul = shl nsw i32 %x, 5
+  %cmp = icmp eq i32 %mul, 0
+  ret i1 %cmp
+}
+
+define <2 x i1> @icmp_shl_nsw_eq_vec(<2 x i32> %x) {
+; CHECK-LABEL: @icmp_shl_nsw_eq_vec(
+; CHECK-NEXT:    [[CMP:%.*]] = icmp eq <2 x i32> %x, zeroinitializer
+; CHECK-NEXT:    ret <2 x i1> [[CMP]]
+;
+  %mul = shl nsw <2 x i32> %x, <i32 5, i32 5>
+  %cmp = icmp eq <2 x i32> %mul, zeroinitializer
+  ret <2 x i1> %cmp
+}
+
+; icmp sgt with shl nsw with a constant compare operand and constant
+; shift amount can always be reduced to icmp sgt alone.
+
+; Known bits analysis turns this into an equality predicate.
+
+define i1 @icmp_sgt1(i8 %x) {
+; CHECK-LABEL: @icmp_sgt1(
+; CHECK-NEXT:    [[CMP:%.*]] = icmp ne i8 %x, -64
+; CHECK-NEXT:    ret i1 [[CMP]]
+;
+  %shl = shl nsw i8 %x, 1
+  %cmp = icmp sgt i8 %shl, -128
+  ret i1 %cmp
+}
+
+define i1 @icmp_sgt2(i8 %x) {
+; CHECK-LABEL: @icmp_sgt2(
+; CHECK-NEXT:    [[CMP:%.*]] = icmp sgt i8 %x, -64
+; CHECK-NEXT:    ret i1 [[CMP]]
+;
+  %shl = shl nsw i8 %x, 1
+  %cmp = icmp sgt i8 %shl, -127
+  ret i1 %cmp
+}
+
+define i1 @icmp_sgt3(i8 %x) {
+; CHECK-LABEL: @icmp_sgt3(
+; CHECK-NEXT:    [[CMP:%.*]] = icmp sgt i8 %x, -8
+; CHECK-NEXT:    ret i1 [[CMP]]
+;
+  %shl = shl nsw i8 %x, 1
+  %cmp = icmp sgt i8 %shl, -16
+  ret i1 %cmp
+}
+
+define i1 @icmp_sgt4(i8 %x) {
+; CHECK-LABEL: @icmp_sgt4(
+; CHECK-NEXT:    [[CMP:%.*]] = icmp sgt i8 %x, -1
+; CHECK-NEXT:    ret i1 [[CMP]]
+;
+  %shl = shl nsw i8 %x, 1
+  %cmp = icmp sgt i8 %shl, -2
+  ret i1 %cmp
+}
+
+; x >s -1 is a sign bit test.
+; x >s 0 is a sign bit test.
+
+define i1 @icmp_sgt5(i8 %x) {
+; CHECK-LABEL: @icmp_sgt5(
+; CHECK-NEXT:    [[CMP:%.*]] = icmp sgt i8 %x, 0
+; CHECK-NEXT:    ret i1 [[CMP]]
+;
+  %shl = shl nsw i8 %x, 1
+  %cmp = icmp sgt i8 %shl, 1
+  ret i1 %cmp
+}
+
+define i1 @icmp_sgt6(i8 %x) {
+; CHECK-LABEL: @icmp_sgt6(
+; CHECK-NEXT:    [[CMP:%.*]] = icmp sgt i8 %x, 8
+; CHECK-NEXT:    ret i1 [[CMP]]
+;
+  %shl = shl nsw i8 %x, 1
+  %cmp = icmp sgt i8 %shl, 16
+  ret i1 %cmp
+}
+
+define i1 @icmp_sgt7(i8 %x) {
+; CHECK-LABEL: @icmp_sgt7(
+; CHECK-NEXT:    [[CMP:%.*]] = icmp sgt i8 %x, 62
+; CHECK-NEXT:    ret i1 [[CMP]]
+;
+  %shl = shl nsw i8 %x, 1
+  %cmp = icmp sgt i8 %shl, 124
+  ret i1 %cmp
+}
+
+; Known bits analysis turns this into an equality predicate.
+
+define i1 @icmp_sgt8(i8 %x) {
+; CHECK-LABEL: @icmp_sgt8(
+; CHECK-NEXT:    [[CMP:%.*]] = icmp eq i8 %x, 63
+; CHECK-NEXT:    ret i1 [[CMP]]
+;
+  %shl = shl nsw i8 %x, 1
+  %cmp = icmp sgt i8 %shl, 125
+  ret i1 %cmp
+}
+
+; Compares with 126 and 127 are recognized as always false.
+
+; Known bits analysis turns this into an equality predicate.
+
+define i1 @icmp_sgt9(i8 %x) {
+; CHECK-LABEL: @icmp_sgt9(
+; CHECK-NEXT:    [[CMP:%.*]] = icmp ne i8 %x, -1
+; CHECK-NEXT:    ret i1 [[CMP]]
+;
+  %shl = shl nsw i8 %x, 7
+  %cmp = icmp sgt i8 %shl, -128
+  ret i1 %cmp
+}
+
+define i1 @icmp_sgt10(i8 %x) {
+; CHECK-LABEL: @icmp_sgt10(
+; CHECK-NEXT:    [[CMP:%.*]] = icmp sgt i8 %x, -1
+; CHECK-NEXT:    ret i1 [[CMP]]
+;
+  %shl = shl nsw i8 %x, 7
+  %cmp = icmp sgt i8 %shl, -127
+  ret i1 %cmp
+}
+
+define i1 @icmp_sgt11(i8 %x) {
+; CHECK-LABEL: @icmp_sgt11(
+; CHECK-NEXT:    [[CMP:%.*]] = icmp sgt i8 %x, -1
+; CHECK-NEXT:    ret i1 [[CMP]]
+;
+  %shl = shl nsw i8 %x, 7
+  %cmp = icmp sgt i8 %shl, -2
+  ret i1 %cmp
+}
+
+; Splat vector version should fold the same way.
+
+define <2 x i1> @icmp_sgt11_vec(<2 x i8> %x) {
+; CHECK-LABEL: @icmp_sgt11_vec(
+; CHECK-NEXT:    [[CMP:%.*]] = icmp sgt <2 x i8> %x, <i8 -1, i8 -1>
+; CHECK-NEXT:    ret <2 x i1> [[CMP]]
+;
+  %shl = shl nsw <2 x i8> %x, <i8 7, i8 7>
+  %cmp = icmp sgt <2 x i8> %shl, <i8 -2, i8 -2>
+  ret <2 x i1> %cmp
+}
+
+; Known bits analysis returns false for compares with >=0.
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;
+; Repeat the shl nsw + sgt tests with predicate changed to 'sle'.
+;
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+
+; Known bits analysis turns this into an equality predicate.
+
+define i1 @icmp_sle1(i8 %x) {
+; CHECK-LABEL: @icmp_sle1(
+; CHECK-NEXT:    [[CMP:%.*]] = icmp eq i8 %x, -64
+; CHECK-NEXT:    ret i1 [[CMP]]
+;
+  %shl = shl nsw i8 %x, 1
+  %cmp = icmp sle i8 %shl, -128
+  ret i1 %cmp
+}
+
+define i1 @icmp_sle2(i8 %x) {
+; CHECK-LABEL: @icmp_sle2(
+; CHECK-NEXT:    [[CMP:%.*]] = icmp slt i8 %x, -63
+; CHECK-NEXT:    ret i1 [[CMP]]
+;
+  %shl = shl nsw i8 %x, 1
+  %cmp = icmp sle i8 %shl, -127
+  ret i1 %cmp
+}
+
+define i1 @icmp_sle3(i8 %x) {
+; CHECK-LABEL: @icmp_sle3(
+; CHECK-NEXT:    [[CMP:%.*]] = icmp slt i8 %x, -7
+; CHECK-NEXT:    ret i1 [[CMP]]
+;
+  %shl = shl nsw i8 %x, 1
+  %cmp = icmp sle i8 %shl, -16
+  ret i1 %cmp
+}
+
+define i1 @icmp_sle4(i8 %x) {
+; CHECK-LABEL: @icmp_sle4(
+; CHECK-NEXT:    [[CMP:%.*]] = icmp slt i8 %x, 0
+; CHECK-NEXT:    ret i1 [[CMP]]
+;
+  %shl = shl nsw i8 %x, 1
+  %cmp = icmp sle i8 %shl, -2
+  ret i1 %cmp
+}
+
+; x <=s -1 is a sign bit test.
+; x <=s 0 is a sign bit test.
+
+define i1 @icmp_sle5(i8 %x) {
+; CHECK-LABEL: @icmp_sle5(
+; CHECK-NEXT:    [[CMP:%.*]] = icmp slt i8 %x, 1
+; CHECK-NEXT:    ret i1 [[CMP]]
+;
+  %shl = shl nsw i8 %x, 1
+  %cmp = icmp sle i8 %shl, 1
+  ret i1 %cmp
+}
+
+define i1 @icmp_sle6(i8 %x) {
+; CHECK-LABEL: @icmp_sle6(
+; CHECK-NEXT:    [[CMP:%.*]] = icmp slt i8 %x, 9
+; CHECK-NEXT:    ret i1 [[CMP]]
+;
+  %shl = shl nsw i8 %x, 1
+  %cmp = icmp sle i8 %shl, 16
+  ret i1 %cmp
+}
+
+define i1 @icmp_sle7(i8 %x) {
+; CHECK-LABEL: @icmp_sle7(
+; CHECK-NEXT:    [[CMP:%.*]] = icmp slt i8 %x, 63
+; CHECK-NEXT:    ret i1 [[CMP]]
+;
+  %shl = shl nsw i8 %x, 1
+  %cmp = icmp sle i8 %shl, 124
+  ret i1 %cmp
+}
+
+; Known bits analysis turns this into an equality predicate.
+
+define i1 @icmp_sle8(i8 %x) {
+; CHECK-LABEL: @icmp_sle8(
+; CHECK-NEXT:    [[CMP:%.*]] = icmp ne i8 %x, 63
+; CHECK-NEXT:    ret i1 [[CMP]]
+;
+  %shl = shl nsw i8 %x, 1
+  %cmp = icmp sle i8 %shl, 125
+  ret i1 %cmp
+}
+
+; Compares with 126 and 127 are recognized as always true.
+
+; Known bits analysis turns this into an equality predicate.
+
+define i1 @icmp_sle9(i8 %x) {
+; CHECK-LABEL: @icmp_sle9(
+; CHECK-NEXT:    [[CMP:%.*]] = icmp eq i8 %x, -1
+; CHECK-NEXT:    ret i1 [[CMP]]
+;
+  %shl = shl nsw i8 %x, 7
+  %cmp = icmp sle i8 %shl, -128
+  ret i1 %cmp
+}
+
+define i1 @icmp_sle10(i8 %x) {
+; CHECK-LABEL: @icmp_sle10(
+; CHECK-NEXT:    [[CMP:%.*]] = icmp slt i8 %x, 0
+; CHECK-NEXT:    ret i1 [[CMP]]
+;
+  %shl = shl nsw i8 %x, 7
+  %cmp = icmp sle i8 %shl, -127
+  ret i1 %cmp
+}
+
+define i1 @icmp_sle11(i8 %x) {
+; CHECK-LABEL: @icmp_sle11(
+; CHECK-NEXT:    [[CMP:%.*]] = icmp slt i8 %x, 0
+; CHECK-NEXT:    ret i1 [[CMP]]
+;
+  %shl = shl nsw i8 %x, 7
+  %cmp = icmp sle i8 %shl, -2
+  ret i1 %cmp
+}
+
+; Some of the earlier sgt/sle tests are transformed to eq/ne, but try a couple
+; of those explicitly, so we know no intermediate transforms are necessary.
+
+define i1 @icmp_eq1(i8 %x) {
+; CHECK-LABEL: @icmp_eq1(
+; CHECK-NEXT:    [[CMP:%.*]] = icmp eq i8 %x, 6
+; CHECK-NEXT:    ret i1 [[CMP]]
+;
+  %shl = shl nsw i8 %x, 1
+  %cmp = icmp eq i8 %shl, 12
+  ret i1 %cmp
+}
+
+define i1 @icmp_ne1(i8 %x) {
+; CHECK-LABEL: @icmp_ne1(
+; CHECK-NEXT:    [[CMP:%.*]] = icmp ne i8 %x, -2
+; CHECK-NEXT:    ret i1 [[CMP]]
+;
+  %shl = shl nsw i8 %x, 6
+  %cmp = icmp ne i8 %shl, -128
+  ret i1 %cmp
+}
+