From 57f4dcfe154fb55eebab3039ab9e4b62ab959a31 Mon Sep 17 00:00:00 2001
From: Simon Pilgrim <llvm-dev@redking.me.uk>
Date: Fri, 8 Apr 2022 16:55:44 +0100
Subject: [PATCH] [InstCombine] Add sub(add(x,y),minmax(x,y)) -> maxmin(x,y)
 tests

Based on Issue #37628
---
 llvm/test/Transforms/InstCombine/sub-minmax.ll | 121 +++++++++++++++++++++++++
 1 file changed, 121 insertions(+)

diff --git a/llvm/test/Transforms/InstCombine/sub-minmax.ll b/llvm/test/Transforms/InstCombine/sub-minmax.ll
index 2deca35..4430c7a 100644
--- a/llvm/test/Transforms/InstCombine/sub-minmax.ll
+++ b/llvm/test/Transforms/InstCombine/sub-minmax.ll
@@ -621,5 +621,126 @@ define i8 @umin_sub_op0_use(i8 %x, i8 %y) {
   ret i8 %r
 }
 
+;
+; TODO: sub(add(X,Y), s/umin(X,Y)) --> s/umax(X,Y)
+; TODO: sub(add(X,Y), s/umax(X,Y)) --> s/umin(X,Y)
+;
+
+define i8 @diff_add_smin(i8 %x, i8 %y) {
+; CHECK-LABEL: @diff_add_smin(
+; CHECK-NEXT:    [[A:%.*]] = add i8 [[X:%.*]], [[Y:%.*]]
+; CHECK-NEXT:    [[M:%.*]] = call i8 @llvm.smin.i8(i8 [[X]], i8 [[Y]])
+; CHECK-NEXT:    [[S:%.*]] = sub i8 [[A]], [[M]]
+; CHECK-NEXT:    ret i8 [[S]]
+;
+  %a = add i8 %x, %y
+  %m = call i8 @llvm.smin.i8(i8 %x, i8 %y)
+  %s = sub i8 %a, %m
+  ret i8 %s
+}
+
+define i8 @diff_add_smax(i8 %x, i8 %y) {
+; CHECK-LABEL: @diff_add_smax(
+; CHECK-NEXT:    [[A:%.*]] = add i8 [[X:%.*]], [[Y:%.*]]
+; CHECK-NEXT:    [[M:%.*]] = call i8 @llvm.smax.i8(i8 [[Y]], i8 [[X]])
+; CHECK-NEXT:    [[S:%.*]] = sub i8 [[A]], [[M]]
+; CHECK-NEXT:    ret i8 [[S]]
+;
+  %a = add i8 %x, %y
+  %m = call i8 @llvm.smax.i8(i8 %y, i8 %x)
+  %s = sub i8 %a, %m
+  ret i8 %s
+}
+
+define i8 @diff_add_umin(i8 %x, i8 %y) {
+; CHECK-LABEL: @diff_add_umin(
+; CHECK-NEXT:    [[A:%.*]] = add i8 [[X:%.*]], [[Y:%.*]]
+; CHECK-NEXT:    [[M:%.*]] = call i8 @llvm.umin.i8(i8 [[X]], i8 [[Y]])
+; CHECK-NEXT:    [[S:%.*]] = sub i8 [[A]], [[M]]
+; CHECK-NEXT:    ret i8 [[S]]
+;
+  %a = add i8 %x, %y
+  %m = call i8 @llvm.umin.i8(i8 %x, i8 %y)
+  %s = sub i8 %a, %m
+  ret i8 %s
+}
+
+define i8 @diff_add_umax(i8 %x, i8 %y) {
+; CHECK-LABEL: @diff_add_umax(
+; CHECK-NEXT:    [[A:%.*]] = add i8 [[X:%.*]], [[Y:%.*]]
+; CHECK-NEXT:    [[M:%.*]] = call i8 @llvm.umax.i8(i8 [[Y]], i8 [[X]])
+; CHECK-NEXT:    [[S:%.*]] = sub i8 [[A]], [[M]]
+; CHECK-NEXT:    ret i8 [[S]]
+;
+  %a = add i8 %x, %y
+  %m = call i8 @llvm.umax.i8(i8 %y, i8 %x)
+  %s = sub i8 %a, %m
+  ret i8 %s
+}
+
+define i8 @diff_add_smin_use(i8 %x, i8 %y) {
+; CHECK-LABEL: @diff_add_smin_use(
+; CHECK-NEXT:    [[A:%.*]] = add i8 [[X:%.*]], [[Y:%.*]]
+; CHECK-NEXT:    [[M:%.*]] = call i8 @llvm.smin.i8(i8 [[X]], i8 [[Y]])
+; CHECK-NEXT:    [[S:%.*]] = sub i8 [[A]], [[M]]
+; CHECK-NEXT:    call void @use8(i8 [[M]])
+; CHECK-NEXT:    ret i8 [[S]]
+;
+  %a = add i8 %x, %y
+  %m = call i8 @llvm.smin.i8(i8 %x, i8 %y)
+  %s = sub i8 %a, %m
+  call void @use8(i8 %m)
+  ret i8 %s
+}
+
+define i8 @diff_add_use_smax(i8 %x, i8 %y) {
+; CHECK-LABEL: @diff_add_use_smax(
+; CHECK-NEXT:    [[A:%.*]] = add i8 [[X:%.*]], [[Y:%.*]]
+; CHECK-NEXT:    [[M:%.*]] = call i8 @llvm.smax.i8(i8 [[Y]], i8 [[X]])
+; CHECK-NEXT:    [[S:%.*]] = sub i8 [[A]], [[M]]
+; CHECK-NEXT:    call void @use8(i8 [[A]])
+; CHECK-NEXT:    ret i8 [[S]]
+;
+  %a = add i8 %x, %y
+  %m = call i8 @llvm.smax.i8(i8 %y, i8 %x)
+  %s = sub i8 %a, %m
+  call void @use8(i8 %a)
+  ret i8 %s
+}
+
+define i8 @diff_add_use_umin_use(i8 %x, i8 %y) {
+; CHECK-LABEL: @diff_add_use_umin_use(
+; CHECK-NEXT:    [[A:%.*]] = add i8 [[X:%.*]], [[Y:%.*]]
+; CHECK-NEXT:    [[M:%.*]] = call i8 @llvm.umin.i8(i8 [[X]], i8 [[Y]])
+; CHECK-NEXT:    [[S:%.*]] = sub i8 [[A]], [[M]]
+; CHECK-NEXT:    call void @use8(i8 [[A]])
+; CHECK-NEXT:    call void @use8(i8 [[M]])
+; CHECK-NEXT:    ret i8 [[S]]
+;
+  %a = add i8 %x, %y
+  %m = call i8 @llvm.umin.i8(i8 %x, i8 %y)
+  %s = sub i8 %a, %m
+  call void @use8(i8 %a)
+  call void @use8(i8 %m)
+  ret i8 %s
+}
+
+;
+; TODO: sub(add(X,Y),umin(Y,Z)) --> add(X,usubsat(Y,Z))
+;
+
+define i8 @sub_add_umin(i8 %x, i8 %y, i8 %z) {
+; CHECK-LABEL: @sub_add_umin(
+; CHECK-NEXT:    [[A:%.*]] = add i8 [[X:%.*]], [[Y:%.*]]
+; CHECK-NEXT:    [[M:%.*]] = call i8 @llvm.umin.i8(i8 [[Y]], i8 [[Z:%.*]])
+; CHECK-NEXT:    [[S:%.*]] = sub i8 [[A]], [[M]]
+; CHECK-NEXT:    ret i8 [[S]]
+;
+  %a = add i8 %x, %y
+  %m = call i8 @llvm.umin.i8(i8 %y, i8 %z)
+  %s = sub i8 %a, %m
+  ret i8 %s
+}
+
 declare void @use8(i8)
 declare void @use32(i32 %u)
-- 
2.7.4