[InstCombine] Add tests for udiv->lshr fold with min/max intrinsics (NFC)

diff --git a/llvm/test/Transforms/InstCombine/div-shift.ll b/llvm/test/Transforms/InstCombine/div-shift.ll
index 6d285ab..a2399df 100644 (file)
--- a/llvm/test/Transforms/InstCombine/div-shift.ll
+++ b/llvm/test/Transforms/InstCombine/div-shift.ll
@@ -1,6 +1,13 @@
 ; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
 ; RUN: opt < %s -passes=instcombine -S | FileCheck %s
 
+declare void @use(i8)
+
+declare i8 @llvm.umin.i8(i8, i8)
+declare i8 @llvm.umax.i8(i8, i8)
+declare i8 @llvm.smin.i8(i8, i8)
+declare i8 @llvm.smax.i8(i8, i8)
+
 define i32 @t1(i16 zeroext %x, i32 %y) {
 ; CHECK-LABEL: @t1(
 ; CHECK-NEXT:  entry:
@@ -99,6 +106,100 @@ define i32 @t6(i32 %x, i32 %z) {
   ret i32 %y
 }
 
+define i8 @udiv_umin(i8 %x, i8 %y, i8 %z) {
+; CHECK-LABEL: @udiv_umin(
+; CHECK-NEXT:    [[Y2:%.*]] = shl i8 1, [[Y:%.*]]
+; CHECK-NEXT:    [[Z2:%.*]] = shl i8 1, [[Z:%.*]]
+; CHECK-NEXT:    [[M:%.*]] = call i8 @llvm.umin.i8(i8 [[Y2]], i8 [[Z2]])
+; CHECK-NEXT:    [[D:%.*]] = udiv i8 [[X:%.*]], [[M]]
+; CHECK-NEXT:    ret i8 [[D]]
+;
+  %y2 = shl i8 1, %y
+  %z2 = shl i8 1, %z
+  %m = call i8 @llvm.umin.i8(i8 %y2, i8 %z2)
+  %d = udiv i8 %x, %m
+  ret i8 %d
+}
+
+define i8 @udiv_umax(i8 %x, i8 %y, i8 %z) {
+; CHECK-LABEL: @udiv_umax(
+; CHECK-NEXT:    [[Y2:%.*]] = shl i8 1, [[Y:%.*]]
+; CHECK-NEXT:    [[Z2:%.*]] = shl i8 1, [[Z:%.*]]
+; CHECK-NEXT:    [[M:%.*]] = call i8 @llvm.umax.i8(i8 [[Y2]], i8 [[Z2]])
+; CHECK-NEXT:    [[D:%.*]] = udiv i8 [[X:%.*]], [[M]]
+; CHECK-NEXT:    ret i8 [[D]]
+;
+  %y2 = shl i8 1, %y
+  %z2 = shl i8 1, %z
+  %m = call i8 @llvm.umax.i8(i8 %y2, i8 %z2)
+  %d = udiv i8 %x, %m
+  ret i8 %d
+}
+
+; Negative test, cannot take exact log2
+define i8 @udiv_umin_(i8 %x, i8 %y, i8 %z) {
+; CHECK-LABEL: @udiv_umin_(
+; CHECK-NEXT:    [[Y2:%.*]] = shl i8 1, [[Y:%.*]]
+; CHECK-NEXT:    [[M:%.*]] = call i8 @llvm.umin.i8(i8 [[Y2]], i8 [[Z:%.*]])
+; CHECK-NEXT:    [[D:%.*]] = udiv i8 [[X:%.*]], [[M]]
+; CHECK-NEXT:    ret i8 [[D]]
+;
+  %y2 = shl i8 1, %y
+  %m = call i8 @llvm.umin.i8(i8 %y2, i8 %z)
+  %d = udiv i8 %x, %m
+  ret i8 %d
+}
+
+; Negative test, extra use
+define i8 @udiv_umin_extra_use(i8 %x, i8 %y, i8 %z) {
+; CHECK-LABEL: @udiv_umin_extra_use(
+; CHECK-NEXT:    [[Y2:%.*]] = shl i8 1, [[Y:%.*]]
+; CHECK-NEXT:    [[Z2:%.*]] = shl i8 1, [[Z:%.*]]
+; CHECK-NEXT:    [[M:%.*]] = call i8 @llvm.umin.i8(i8 [[Y2]], i8 [[Z2]])
+; CHECK-NEXT:    call void @use(i8 [[M]])
+; CHECK-NEXT:    [[D:%.*]] = udiv i8 [[X:%.*]], [[M]]
+; CHECK-NEXT:    ret i8 [[D]]
+;
+  %y2 = shl i8 1, %y
+  %z2 = shl i8 1, %z
+  %m = call i8 @llvm.umin.i8(i8 %y2, i8 %z2)
+  call void @use(i8 %m)
+  %d = udiv i8 %x, %m
+  ret i8 %d
+}
+
+; Negative test, signed min/max
+define i8 @udiv_smin(i8 %x, i8 %y, i8 %z) {
+; CHECK-LABEL: @udiv_smin(
+; CHECK-NEXT:    [[Y2:%.*]] = shl i8 1, [[Y:%.*]]
+; CHECK-NEXT:    [[Z2:%.*]] = shl i8 1, [[Z:%.*]]
+; CHECK-NEXT:    [[M:%.*]] = call i8 @llvm.smin.i8(i8 [[Y2]], i8 [[Z2]])
+; CHECK-NEXT:    [[D:%.*]] = udiv i8 [[X:%.*]], [[M]]
+; CHECK-NEXT:    ret i8 [[D]]
+;
+  %y2 = shl i8 1, %y
+  %z2 = shl i8 1, %z
+  %m = call i8 @llvm.smin.i8(i8 %y2, i8 %z2)
+  %d = udiv i8 %x, %m
+  ret i8 %d
+}
+
+; Negative test, signed min/max
+define i8 @udiv_smax(i8 %x, i8 %y, i8 %z) {
+; CHECK-LABEL: @udiv_smax(
+; CHECK-NEXT:    [[Y2:%.*]] = shl i8 1, [[Y:%.*]]
+; CHECK-NEXT:    [[Z2:%.*]] = shl i8 1, [[Z:%.*]]
+; CHECK-NEXT:    [[M:%.*]] = call i8 @llvm.smax.i8(i8 [[Y2]], i8 [[Z2]])
+; CHECK-NEXT:    [[D:%.*]] = udiv i8 [[X:%.*]], [[M]]
+; CHECK-NEXT:    ret i8 [[D]]
+;
+  %y2 = shl i8 1, %y
+  %z2 = shl i8 1, %z
+  %m = call i8 @llvm.smax.i8(i8 %y2, i8 %z2)
+  %d = udiv i8 %x, %m
+  ret i8 %d
+}
+
 ; (X << C1) / X -> 1 << C1 optimizations
 
 define i32 @t7(i32 %x) {