From eb85e5df9f87bde0c5be50dd04ea441cb4512e56 Mon Sep 17 00:00:00 2001
From: Sanjay Patel <spatel@rotateright.com>
Date: Tue, 20 Aug 2019 13:39:17 +0000
Subject: [PATCH] [InstCombine] simplify min/max of min/max with same operands
 (PR35607)

This is the original integer variant requested in:
https://bugs.llvm.org/show_bug.cgi?id=35607

As noted in the TODO and several similar TODOs around this block,
we could do this in instsimplify, but then it would cost more
because we would be trying to match min/max via ValueTracking
in 2 different places.

There are 4 commuted variants for each of smin/smax/umin/umax
that are not matched here. There are also icmp predicate variants
that are not included in the affected test file because they are
already handled by instsimplify by folding the final icmp to
true/false.

https://rise4fun.com/Alive/3KVc

  Name: smax(smax, smin)
  %c1 = icmp slt i32 %x, %y
  %c2 = icmp slt i32 %y, %x
  %min = select i1 %c1, i32 %x, i32 %y
  %max = select i1 %c2, i32 %x, i32 %y
  %c3 = icmp sgt i32 %max, %min
  %r = select i1 %c3, i32 %max, i32 %min
  =>
  %r = %max

  Name: smin(smax, smin)
  %c1 = icmp slt i32 %x, %y
  %c2 = icmp slt i32 %y, %x
  %min = select i1 %c1, i32 %x, i32 %y
  %max = select i1 %c2, i32 %x, i32 %y
  %c3 = icmp sgt i32 %max, %min
  %r = select i1 %c3, i32 %min, i32 %max
  =>
  %r = %min

  Name: umax(umax, umin)
  %c1 = icmp ult i32 %x, %y
  %c2 = icmp ult i32 %y, %x
  %min = select i1 %c1, i32 %x, i32 %y
  %max = select i1 %c2, i32 %x, i32 %y
  %c3 = icmp ult i32 %min, %max
  %r = select i1 %c3, i32 %max, i32 %min
  =>
  %r = %max

  Name: umin(umax, umin)
  %c1 = icmp ult i32 %x, %y
  %c2 = icmp ult i32 %y, %x
  %min = select i1 %c1, i32 %x, i32 %y
  %max = select i1 %c2, i32 %x, i32 %y
  %c3 = icmp ult i32 %min, %max
  %r = select i1 %c3, i32 %min, i32 %max
  =>
  %r = %min

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@369386 91177308-0d34-0410-b5e6-96231b3b80d8
---
 .../InstCombine/InstCombineSelect.cpp         |  10 ++
 .../InstCombine/minmax-of-minmax.ll           | 136 ++++++------------
 2 files changed, 50 insertions(+), 96 deletions(-)

diff --git a/lib/Transforms/InstCombine/InstCombineSelect.cpp b/lib/Transforms/InstCombine/InstCombineSelect.cpp
index c257cf9e1d0..2bfd11a2574 100644
--- a/lib/Transforms/InstCombine/InstCombineSelect.cpp
+++ b/lib/Transforms/InstCombine/InstCombineSelect.cpp
@@ -1457,6 +1457,16 @@ Instruction *InstCombiner::foldSPFofSPF(Instruction *Inner,
     }
   }
 
+  // max(max(A, B), min(A, B)) --> max(A, B)
+  // min(min(A, B), max(A, B)) --> min(A, B)
+  // TODO: This could be done in instsimplify.
+  if (SPF1 == SPF2 &&
+      ((SPF1 == SPF_UMIN && match(C, m_c_UMax(m_Specific(A), m_Specific(B)))) ||
+       (SPF1 == SPF_SMIN && match(C, m_c_SMax(m_Specific(A), m_Specific(B)))) ||
+       (SPF1 == SPF_UMAX && match(C, m_c_UMin(m_Specific(A), m_Specific(B)))) ||
+       (SPF1 == SPF_SMAX && match(C, m_c_SMin(m_Specific(A), m_Specific(B))))))
+    return replaceInstUsesWith(Outer, Inner);
+
   // ABS(ABS(X)) -> ABS(X)
   // NABS(NABS(X)) -> NABS(X)
   // TODO: This could be done in instsimplify.
diff --git a/test/Transforms/InstCombine/minmax-of-minmax.ll b/test/Transforms/InstCombine/minmax-of-minmax.ll
index 06a361f6bae..58f2099e436 100644
--- a/test/Transforms/InstCombine/minmax-of-minmax.ll
+++ b/test/Transforms/InstCombine/minmax-of-minmax.ll
@@ -3,13 +3,9 @@
 
 define i32 @smax_of_smax_smin_commute0(i32 %x, i32 %y) {
 ; CHECK-LABEL: @smax_of_smax_smin_commute0(
-; CHECK-NEXT:    [[CMP1:%.*]] = icmp slt i32 [[X:%.*]], [[Y:%.*]]
-; CHECK-NEXT:    [[MIN:%.*]] = select i1 [[CMP1]], i32 [[X]], i32 [[Y]]
-; CHECK-NEXT:    [[CMP2:%.*]] = icmp slt i32 [[Y]], [[X]]
+; CHECK-NEXT:    [[CMP2:%.*]] = icmp slt i32 [[Y:%.*]], [[X:%.*]]
 ; CHECK-NEXT:    [[MAX:%.*]] = select i1 [[CMP2]], i32 [[X]], i32 [[Y]]
-; CHECK-NEXT:    [[CMP3:%.*]] = icmp sgt i32 [[MAX]], [[MIN]]
-; CHECK-NEXT:    [[R:%.*]] = select i1 [[CMP3]], i32 [[MAX]], i32 [[MIN]]
-; CHECK-NEXT:    ret i32 [[R]]
+; CHECK-NEXT:    ret i32 [[MAX]]
 ;
   %cmp1 = icmp slt i32 %x, %y
   %min = select i1 %cmp1, i32 %x, i32 %y
@@ -22,13 +18,9 @@ define i32 @smax_of_smax_smin_commute0(i32 %x, i32 %y) {
 
 define i32 @smax_of_smax_smin_commute1(i32 %x, i32 %y) {
 ; CHECK-LABEL: @smax_of_smax_smin_commute1(
-; CHECK-NEXT:    [[CMP1:%.*]] = icmp sgt i32 [[X:%.*]], [[Y:%.*]]
-; CHECK-NEXT:    [[MIN:%.*]] = select i1 [[CMP1]], i32 [[Y]], i32 [[X]]
-; CHECK-NEXT:    [[CMP2:%.*]] = icmp sgt i32 [[X]], [[Y]]
+; CHECK-NEXT:    [[CMP2:%.*]] = icmp sgt i32 [[X:%.*]], [[Y:%.*]]
 ; CHECK-NEXT:    [[MAX:%.*]] = select i1 [[CMP2]], i32 [[X]], i32 [[Y]]
-; CHECK-NEXT:    [[CMP3:%.*]] = icmp sgt i32 [[MAX]], [[MIN]]
-; CHECK-NEXT:    [[R:%.*]] = select i1 [[CMP3]], i32 [[MAX]], i32 [[MIN]]
-; CHECK-NEXT:    ret i32 [[R]]
+; CHECK-NEXT:    ret i32 [[MAX]]
 ;
   %cmp1 = icmp sgt i32 %x, %y
   %min = select i1 %cmp1, i32 %y, i32 %x
@@ -41,13 +33,9 @@ define i32 @smax_of_smax_smin_commute1(i32 %x, i32 %y) {
 
 define i32 @smax_of_smax_smin_commute2(i32 %x, i32 %y) {
 ; CHECK-LABEL: @smax_of_smax_smin_commute2(
-; CHECK-NEXT:    [[CMP1:%.*]] = icmp slt i32 [[X:%.*]], [[Y:%.*]]
-; CHECK-NEXT:    [[MIN:%.*]] = select i1 [[CMP1]], i32 [[X]], i32 [[Y]]
-; CHECK-NEXT:    [[CMP2:%.*]] = icmp slt i32 [[Y]], [[X]]
+; CHECK-NEXT:    [[CMP2:%.*]] = icmp slt i32 [[Y:%.*]], [[X:%.*]]
 ; CHECK-NEXT:    [[MAX:%.*]] = select i1 [[CMP2]], i32 [[X]], i32 [[Y]]
-; CHECK-NEXT:    [[CMP3:%.*]] = icmp slt i32 [[MIN]], [[MAX]]
-; CHECK-NEXT:    [[R:%.*]] = select i1 [[CMP3]], i32 [[MAX]], i32 [[MIN]]
-; CHECK-NEXT:    ret i32 [[R]]
+; CHECK-NEXT:    ret i32 [[MAX]]
 ;
   %cmp1 = icmp slt i32 %x, %y
   %min = select i1 %cmp1, i32 %x, i32 %y
@@ -60,13 +48,9 @@ define i32 @smax_of_smax_smin_commute2(i32 %x, i32 %y) {
 
 define <2 x i32> @smax_of_smax_smin_commute3(<2 x i32> %x, <2 x i32> %y) {
 ; CHECK-LABEL: @smax_of_smax_smin_commute3(
-; CHECK-NEXT:    [[CMP1:%.*]] = icmp sgt <2 x i32> [[X:%.*]], [[Y:%.*]]
-; CHECK-NEXT:    [[MIN:%.*]] = select <2 x i1> [[CMP1]], <2 x i32> [[Y]], <2 x i32> [[X]]
-; CHECK-NEXT:    [[CMP2:%.*]] = icmp sgt <2 x i32> [[X]], [[Y]]
+; CHECK-NEXT:    [[CMP2:%.*]] = icmp sgt <2 x i32> [[X:%.*]], [[Y:%.*]]
 ; CHECK-NEXT:    [[MAX:%.*]] = select <2 x i1> [[CMP2]], <2 x i32> [[X]], <2 x i32> [[Y]]
-; CHECK-NEXT:    [[CMP3:%.*]] = icmp slt <2 x i32> [[MIN]], [[MAX]]
-; CHECK-NEXT:    [[R:%.*]] = select <2 x i1> [[CMP3]], <2 x i32> [[MAX]], <2 x i32> [[MIN]]
-; CHECK-NEXT:    ret <2 x i32> [[R]]
+; CHECK-NEXT:    ret <2 x i32> [[MAX]]
 ;
   %cmp1 = icmp sgt <2 x i32> %x, %y
   %min = select <2 x i1> %cmp1, <2 x i32> %y, <2 x i32> %x
@@ -79,13 +63,9 @@ define <2 x i32> @smax_of_smax_smin_commute3(<2 x i32> %x, <2 x i32> %y) {
 
 define i32 @smin_of_smin_smax_commute0(i32 %x, i32 %y) {
 ; CHECK-LABEL: @smin_of_smin_smax_commute0(
-; CHECK-NEXT:    [[CMP1:%.*]] = icmp sgt i32 [[X:%.*]], [[Y:%.*]]
-; CHECK-NEXT:    [[MAX:%.*]] = select i1 [[CMP1]], i32 [[X]], i32 [[Y]]
-; CHECK-NEXT:    [[CMP2:%.*]] = icmp sgt i32 [[Y]], [[X]]
+; CHECK-NEXT:    [[CMP2:%.*]] = icmp sgt i32 [[Y:%.*]], [[X:%.*]]
 ; CHECK-NEXT:    [[MIN:%.*]] = select i1 [[CMP2]], i32 [[X]], i32 [[Y]]
-; CHECK-NEXT:    [[CMP3:%.*]] = icmp sgt i32 [[MAX]], [[MIN]]
-; CHECK-NEXT:    [[R:%.*]] = select i1 [[CMP3]], i32 [[MIN]], i32 [[MAX]]
-; CHECK-NEXT:    ret i32 [[R]]
+; CHECK-NEXT:    ret i32 [[MIN]]
 ;
   %cmp1 = icmp sgt i32 %x, %y
   %max = select i1 %cmp1, i32 %x, i32 %y
@@ -98,13 +78,9 @@ define i32 @smin_of_smin_smax_commute0(i32 %x, i32 %y) {
 
 define i32 @smin_of_smin_smax_commute1(i32 %x, i32 %y) {
 ; CHECK-LABEL: @smin_of_smin_smax_commute1(
-; CHECK-NEXT:    [[CMP1:%.*]] = icmp slt i32 [[X:%.*]], [[Y:%.*]]
-; CHECK-NEXT:    [[MAX:%.*]] = select i1 [[CMP1]], i32 [[Y]], i32 [[X]]
-; CHECK-NEXT:    [[CMP2:%.*]] = icmp slt i32 [[X]], [[Y]]
+; CHECK-NEXT:    [[CMP2:%.*]] = icmp slt i32 [[X:%.*]], [[Y:%.*]]
 ; CHECK-NEXT:    [[MIN:%.*]] = select i1 [[CMP2]], i32 [[X]], i32 [[Y]]
-; CHECK-NEXT:    [[CMP3:%.*]] = icmp sgt i32 [[MAX]], [[MIN]]
-; CHECK-NEXT:    [[R:%.*]] = select i1 [[CMP3]], i32 [[MIN]], i32 [[MAX]]
-; CHECK-NEXT:    ret i32 [[R]]
+; CHECK-NEXT:    ret i32 [[MIN]]
 ;
   %cmp1 = icmp slt i32 %x, %y
   %max = select i1 %cmp1, i32 %y, i32 %x
@@ -117,13 +93,9 @@ define i32 @smin_of_smin_smax_commute1(i32 %x, i32 %y) {
 
 define <2 x i32> @smin_of_smin_smax_commute2(<2 x i32> %x, <2 x i32> %y) {
 ; CHECK-LABEL: @smin_of_smin_smax_commute2(
-; CHECK-NEXT:    [[CMP1:%.*]] = icmp sgt <2 x i32> [[X:%.*]], [[Y:%.*]]
-; CHECK-NEXT:    [[MAX:%.*]] = select <2 x i1> [[CMP1]], <2 x i32> [[X]], <2 x i32> [[Y]]
-; CHECK-NEXT:    [[CMP2:%.*]] = icmp slt <2 x i32> [[X]], [[Y]]
+; CHECK-NEXT:    [[CMP2:%.*]] = icmp slt <2 x i32> [[X:%.*]], [[Y:%.*]]
 ; CHECK-NEXT:    [[MIN:%.*]] = select <2 x i1> [[CMP2]], <2 x i32> [[X]], <2 x i32> [[Y]]
-; CHECK-NEXT:    [[CMP3:%.*]] = icmp slt <2 x i32> [[MIN]], [[MAX]]
-; CHECK-NEXT:    [[R:%.*]] = select <2 x i1> [[CMP3]], <2 x i32> [[MIN]], <2 x i32> [[MAX]]
-; CHECK-NEXT:    ret <2 x i32> [[R]]
+; CHECK-NEXT:    ret <2 x i32> [[MIN]]
 ;
   %cmp1 = icmp sgt <2 x i32> %x, %y
   %max = select <2 x i1> %cmp1, <2 x i32> %x, <2 x i32> %y
@@ -136,13 +108,9 @@ define <2 x i32> @smin_of_smin_smax_commute2(<2 x i32> %x, <2 x i32> %y) {
 
 define i32 @smin_of_smin_smax_commute3(i32 %x, i32 %y) {
 ; CHECK-LABEL: @smin_of_smin_smax_commute3(
-; CHECK-NEXT:    [[CMP1:%.*]] = icmp slt i32 [[X:%.*]], [[Y:%.*]]
-; CHECK-NEXT:    [[MAX:%.*]] = select i1 [[CMP1]], i32 [[Y]], i32 [[X]]
-; CHECK-NEXT:    [[CMP2:%.*]] = icmp sgt i32 [[Y]], [[X]]
+; CHECK-NEXT:    [[CMP2:%.*]] = icmp sgt i32 [[Y:%.*]], [[X:%.*]]
 ; CHECK-NEXT:    [[MIN:%.*]] = select i1 [[CMP2]], i32 [[X]], i32 [[Y]]
-; CHECK-NEXT:    [[CMP3:%.*]] = icmp slt i32 [[MIN]], [[MAX]]
-; CHECK-NEXT:    [[R:%.*]] = select i1 [[CMP3]], i32 [[MIN]], i32 [[MAX]]
-; CHECK-NEXT:    ret i32 [[R]]
+; CHECK-NEXT:    ret i32 [[MIN]]
 ;
   %cmp1 = icmp slt i32 %x, %y
   %max = select i1 %cmp1, i32 %y, i32 %x
@@ -155,13 +123,9 @@ define i32 @smin_of_smin_smax_commute3(i32 %x, i32 %y) {
 
 define i32 @umax_of_umax_umin_commute0(i32 %x, i32 %y) {
 ; CHECK-LABEL: @umax_of_umax_umin_commute0(
-; CHECK-NEXT:    [[CMP1:%.*]] = icmp ult i32 [[X:%.*]], [[Y:%.*]]
-; CHECK-NEXT:    [[MIN:%.*]] = select i1 [[CMP1]], i32 [[X]], i32 [[Y]]
-; CHECK-NEXT:    [[CMP2:%.*]] = icmp ult i32 [[Y]], [[X]]
+; CHECK-NEXT:    [[CMP2:%.*]] = icmp ult i32 [[Y:%.*]], [[X:%.*]]
 ; CHECK-NEXT:    [[MAX:%.*]] = select i1 [[CMP2]], i32 [[X]], i32 [[Y]]
-; CHECK-NEXT:    [[CMP3:%.*]] = icmp ugt i32 [[MAX]], [[MIN]]
-; CHECK-NEXT:    [[R:%.*]] = select i1 [[CMP3]], i32 [[MAX]], i32 [[MIN]]
-; CHECK-NEXT:    ret i32 [[R]]
+; CHECK-NEXT:    ret i32 [[MAX]]
 ;
   %cmp1 = icmp ult i32 %x, %y
   %min = select i1 %cmp1, i32 %x, i32 %y
@@ -174,13 +138,9 @@ define i32 @umax_of_umax_umin_commute0(i32 %x, i32 %y) {
 
 define i32 @umax_of_umax_umin_commute1(i32 %x, i32 %y) {
 ; CHECK-LABEL: @umax_of_umax_umin_commute1(
-; CHECK-NEXT:    [[CMP1:%.*]] = icmp ugt i32 [[X:%.*]], [[Y:%.*]]
-; CHECK-NEXT:    [[MIN:%.*]] = select i1 [[CMP1]], i32 [[Y]], i32 [[X]]
-; CHECK-NEXT:    [[CMP2:%.*]] = icmp ugt i32 [[X]], [[Y]]
+; CHECK-NEXT:    [[CMP2:%.*]] = icmp ugt i32 [[X:%.*]], [[Y:%.*]]
 ; CHECK-NEXT:    [[MAX:%.*]] = select i1 [[CMP2]], i32 [[X]], i32 [[Y]]
-; CHECK-NEXT:    [[CMP3:%.*]] = icmp ugt i32 [[MAX]], [[MIN]]
-; CHECK-NEXT:    [[R:%.*]] = select i1 [[CMP3]], i32 [[MAX]], i32 [[MIN]]
-; CHECK-NEXT:    ret i32 [[R]]
+; CHECK-NEXT:    ret i32 [[MAX]]
 ;
   %cmp1 = icmp ugt i32 %x, %y
   %min = select i1 %cmp1, i32 %y, i32 %x
@@ -193,13 +153,9 @@ define i32 @umax_of_umax_umin_commute1(i32 %x, i32 %y) {
 
 define i32 @umax_of_umax_umin_commute2(i32 %x, i32 %y) {
 ; CHECK-LABEL: @umax_of_umax_umin_commute2(
-; CHECK-NEXT:    [[CMP1:%.*]] = icmp ult i32 [[X:%.*]], [[Y:%.*]]
-; CHECK-NEXT:    [[MIN:%.*]] = select i1 [[CMP1]], i32 [[X]], i32 [[Y]]
-; CHECK-NEXT:    [[CMP2:%.*]] = icmp ult i32 [[Y]], [[X]]
+; CHECK-NEXT:    [[CMP2:%.*]] = icmp ult i32 [[Y:%.*]], [[X:%.*]]
 ; CHECK-NEXT:    [[MAX:%.*]] = select i1 [[CMP2]], i32 [[X]], i32 [[Y]]
-; CHECK-NEXT:    [[CMP3:%.*]] = icmp ult i32 [[MIN]], [[MAX]]
-; CHECK-NEXT:    [[R:%.*]] = select i1 [[CMP3]], i32 [[MAX]], i32 [[MIN]]
-; CHECK-NEXT:    ret i32 [[R]]
+; CHECK-NEXT:    ret i32 [[MAX]]
 ;
   %cmp1 = icmp ult i32 %x, %y
   %min = select i1 %cmp1, i32 %x, i32 %y
@@ -212,13 +168,9 @@ define i32 @umax_of_umax_umin_commute2(i32 %x, i32 %y) {
 
 define <2 x i32> @umax_of_umax_umin_commute3(<2 x i32> %x, <2 x i32> %y) {
 ; CHECK-LABEL: @umax_of_umax_umin_commute3(
-; CHECK-NEXT:    [[CMP1:%.*]] = icmp ugt <2 x i32> [[X:%.*]], [[Y:%.*]]
-; CHECK-NEXT:    [[MIN:%.*]] = select <2 x i1> [[CMP1]], <2 x i32> [[Y]], <2 x i32> [[X]]
-; CHECK-NEXT:    [[CMP2:%.*]] = icmp ugt <2 x i32> [[X]], [[Y]]
+; CHECK-NEXT:    [[CMP2:%.*]] = icmp ugt <2 x i32> [[X:%.*]], [[Y:%.*]]
 ; CHECK-NEXT:    [[MAX:%.*]] = select <2 x i1> [[CMP2]], <2 x i32> [[X]], <2 x i32> [[Y]]
-; CHECK-NEXT:    [[CMP3:%.*]] = icmp ult <2 x i32> [[MIN]], [[MAX]]
-; CHECK-NEXT:    [[R:%.*]] = select <2 x i1> [[CMP3]], <2 x i32> [[MAX]], <2 x i32> [[MIN]]
-; CHECK-NEXT:    ret <2 x i32> [[R]]
+; CHECK-NEXT:    ret <2 x i32> [[MAX]]
 ;
   %cmp1 = icmp ugt <2 x i32> %x, %y
   %min = select <2 x i1> %cmp1, <2 x i32> %y, <2 x i32> %x
@@ -231,13 +183,9 @@ define <2 x i32> @umax_of_umax_umin_commute3(<2 x i32> %x, <2 x i32> %y) {
 
 define i32 @umin_of_umin_umax_commute0(i32 %x, i32 %y) {
 ; CHECK-LABEL: @umin_of_umin_umax_commute0(
-; CHECK-NEXT:    [[CMP1:%.*]] = icmp ugt i32 [[X:%.*]], [[Y:%.*]]
-; CHECK-NEXT:    [[MAX:%.*]] = select i1 [[CMP1]], i32 [[X]], i32 [[Y]]
-; CHECK-NEXT:    [[CMP2:%.*]] = icmp ugt i32 [[Y]], [[X]]
+; CHECK-NEXT:    [[CMP2:%.*]] = icmp ugt i32 [[Y:%.*]], [[X:%.*]]
 ; CHECK-NEXT:    [[MIN:%.*]] = select i1 [[CMP2]], i32 [[X]], i32 [[Y]]
-; CHECK-NEXT:    [[CMP3:%.*]] = icmp ugt i32 [[MAX]], [[MIN]]
-; CHECK-NEXT:    [[R:%.*]] = select i1 [[CMP3]], i32 [[MIN]], i32 [[MAX]]
-; CHECK-NEXT:    ret i32 [[R]]
+; CHECK-NEXT:    ret i32 [[MIN]]
 ;
   %cmp1 = icmp ugt i32 %x, %y
   %max = select i1 %cmp1, i32 %x, i32 %y
@@ -250,13 +198,9 @@ define i32 @umin_of_umin_umax_commute0(i32 %x, i32 %y) {
 
 define i32 @umin_of_umin_umax_commute1(i32 %x, i32 %y) {
 ; CHECK-LABEL: @umin_of_umin_umax_commute1(
-; CHECK-NEXT:    [[CMP1:%.*]] = icmp ult i32 [[X:%.*]], [[Y:%.*]]
-; CHECK-NEXT:    [[MAX:%.*]] = select i1 [[CMP1]], i32 [[Y]], i32 [[X]]
-; CHECK-NEXT:    [[CMP2:%.*]] = icmp ult i32 [[X]], [[Y]]
+; CHECK-NEXT:    [[CMP2:%.*]] = icmp ult i32 [[X:%.*]], [[Y:%.*]]
 ; CHECK-NEXT:    [[MIN:%.*]] = select i1 [[CMP2]], i32 [[X]], i32 [[Y]]
-; CHECK-NEXT:    [[CMP3:%.*]] = icmp ugt i32 [[MAX]], [[MIN]]
-; CHECK-NEXT:    [[R:%.*]] = select i1 [[CMP3]], i32 [[MIN]], i32 [[MAX]]
-; CHECK-NEXT:    ret i32 [[R]]
+; CHECK-NEXT:    ret i32 [[MIN]]
 ;
   %cmp1 = icmp ult i32 %x, %y
   %max = select i1 %cmp1, i32 %y, i32 %x
@@ -269,13 +213,9 @@ define i32 @umin_of_umin_umax_commute1(i32 %x, i32 %y) {
 
 define <2 x i32> @umin_of_umin_umax_commute2(<2 x i32> %x, <2 x i32> %y) {
 ; CHECK-LABEL: @umin_of_umin_umax_commute2(
-; CHECK-NEXT:    [[CMP1:%.*]] = icmp ugt <2 x i32> [[X:%.*]], [[Y:%.*]]
-; CHECK-NEXT:    [[MAX:%.*]] = select <2 x i1> [[CMP1]], <2 x i32> [[X]], <2 x i32> [[Y]]
-; CHECK-NEXT:    [[CMP2:%.*]] = icmp ult <2 x i32> [[X]], [[Y]]
+; CHECK-NEXT:    [[CMP2:%.*]] = icmp ult <2 x i32> [[X:%.*]], [[Y:%.*]]
 ; CHECK-NEXT:    [[MIN:%.*]] = select <2 x i1> [[CMP2]], <2 x i32> [[X]], <2 x i32> [[Y]]
-; CHECK-NEXT:    [[CMP3:%.*]] = icmp ult <2 x i32> [[MIN]], [[MAX]]
-; CHECK-NEXT:    [[R:%.*]] = select <2 x i1> [[CMP3]], <2 x i32> [[MIN]], <2 x i32> [[MAX]]
-; CHECK-NEXT:    ret <2 x i32> [[R]]
+; CHECK-NEXT:    ret <2 x i32> [[MIN]]
 ;
   %cmp1 = icmp ugt <2 x i32> %x, %y
   %max = select <2 x i1> %cmp1, <2 x i32> %x, <2 x i32> %y
@@ -288,13 +228,9 @@ define <2 x i32> @umin_of_umin_umax_commute2(<2 x i32> %x, <2 x i32> %y) {
 
 define i32 @umin_of_umin_umax_commute3(i32 %x, i32 %y) {
 ; CHECK-LABEL: @umin_of_umin_umax_commute3(
-; CHECK-NEXT:    [[CMP1:%.*]] = icmp ult i32 [[X:%.*]], [[Y:%.*]]
-; CHECK-NEXT:    [[MAX:%.*]] = select i1 [[CMP1]], i32 [[Y]], i32 [[X]]
-; CHECK-NEXT:    [[CMP2:%.*]] = icmp ugt i32 [[Y]], [[X]]
+; CHECK-NEXT:    [[CMP2:%.*]] = icmp ugt i32 [[Y:%.*]], [[X:%.*]]
 ; CHECK-NEXT:    [[MIN:%.*]] = select i1 [[CMP2]], i32 [[X]], i32 [[Y]]
-; CHECK-NEXT:    [[CMP3:%.*]] = icmp ult i32 [[MIN]], [[MAX]]
-; CHECK-NEXT:    [[R:%.*]] = select i1 [[CMP3]], i32 [[MIN]], i32 [[MAX]]
-; CHECK-NEXT:    ret i32 [[R]]
+; CHECK-NEXT:    ret i32 [[MIN]]
 ;
   %cmp1 = icmp ult i32 %x, %y
   %max = select i1 %cmp1, i32 %y, i32 %x
@@ -305,6 +241,8 @@ define i32 @umin_of_umin_umax_commute3(i32 %x, i32 %y) {
   ret i32 %r
 }
 
+; Negative test - mismatch of min/max flavor
+
 define i32 @umin_of_smin_umax_wrong_pattern(i32 %x, i32 %y) {
 ; CHECK-LABEL: @umin_of_smin_umax_wrong_pattern(
 ; CHECK-NEXT:    [[CMP1:%.*]] = icmp ugt i32 [[X:%.*]], [[Y:%.*]]
@@ -324,6 +262,8 @@ define i32 @umin_of_smin_umax_wrong_pattern(i32 %x, i32 %y) {
   ret i32 %r
 }
 
+; Negative test - mismatch of min/max flavor
+
 define i32 @smin_of_umin_umax_wrong_pattern2(i32 %x, i32 %y) {
 ; CHECK-LABEL: @smin_of_umin_umax_wrong_pattern2(
 ; CHECK-NEXT:    [[CMP1:%.*]] = icmp ult i32 [[X:%.*]], [[Y:%.*]]
@@ -343,6 +283,8 @@ define i32 @smin_of_umin_umax_wrong_pattern2(i32 %x, i32 %y) {
   ret i32 %r
 }
 
+; Negative test - operands must match
+
 define <2 x i32> @umin_of_umin_umax_wrong_operand(<2 x i32> %x, <2 x i32> %y, <2 x i32> %z) {
 ; CHECK-LABEL: @umin_of_umin_umax_wrong_operand(
 ; CHECK-NEXT:    [[CMP1:%.*]] = icmp ugt <2 x i32> [[X:%.*]], [[Y:%.*]]
@@ -362,6 +304,8 @@ define <2 x i32> @umin_of_umin_umax_wrong_operand(<2 x i32> %x, <2 x i32> %y, <2
   ret <2 x i32> %r
 }
 
+; Negative test - operands must match
+
 define i32 @umin_of_umin_umax_wrong_operand2(i32 %x, i32 %y, i32 %z) {
 ; CHECK-LABEL: @umin_of_umin_umax_wrong_operand2(
 ; CHECK-NEXT:    [[CMP1:%.*]] = icmp ult i32 [[X:%.*]], [[Z:%.*]]
-- 
2.50.1