From 3e9770d2dc28901ba3b7756c0714d8762279cce8 Mon Sep 17 00:00:00 2001
From: Nikita Popov <nikita.ppv@gmail.com>
Date: Mon, 18 Mar 2019 22:26:27 +0000
Subject: [PATCH] Revert "[ValueTracking][InstSimplify] Support min/max selects
 in computeConstantRange()"

This reverts commit 106f0cdefb02afc3064268dc7a71419b409ed2f3.

This change impacts the AMDGPU smed3.ll and umed3.ll codegen tests.

llvm-svn: 356424
---
 llvm/lib/Analysis/ValueTracking.cpp                | 23 +---------------
 llvm/test/Transforms/InstCombine/minmax-fold.ll    | 31 ----------------------
 .../test/Transforms/InstSimplify/cmp_of_min_max.ll | 20 +++++++++++---
 3 files changed, 17 insertions(+), 57 deletions(-)

diff --git a/llvm/lib/Analysis/ValueTracking.cpp b/llvm/lib/Analysis/ValueTracking.cpp
index 2988043..0012378 100644
--- a/llvm/lib/Analysis/ValueTracking.cpp
+++ b/llvm/lib/Analysis/ValueTracking.cpp
@@ -5680,28 +5680,7 @@ static void setLimitsForSelectPattern(const SelectInst &SI, APInt &Lower,
     return;
   }
 
-  const APInt *C;
-  if (!match(LHS, m_APInt(C)) && !match(RHS, m_APInt(C)))
-    return;
-
-  switch (R.Flavor) {
-    case SPF_UMIN:
-      Upper = *C + 1;
-      break;
-    case SPF_UMAX:
-      Lower = *C;
-      break;
-    case SPF_SMIN:
-      Lower = APInt::getSignedMinValue(BitWidth);
-      Upper = *C + 1;
-      break;
-    case SPF_SMAX:
-      Lower = *C;
-      Upper = APInt::getSignedMaxValue(BitWidth) + 1;
-      break;
-    default:
-      break;
-  }
+  // TODO Handle min/max flavors.
 }
 
 ConstantRange llvm::computeConstantRange(const Value *V, bool UseInstrInfo) {
diff --git a/llvm/test/Transforms/InstCombine/minmax-fold.ll b/llvm/test/Transforms/InstCombine/minmax-fold.ll
index 7b66eb4..d312155 100644
--- a/llvm/test/Transforms/InstCombine/minmax-fold.ll
+++ b/llvm/test/Transforms/InstCombine/minmax-fold.ll
@@ -533,37 +533,6 @@ define i32 @clamp_check_for_no_infinite_loop2(i32 %i) {
   ret i32 %res
 }
 
-; Check that there is no infinite loop because of reverse cmp transformation:
-; (icmp slt smax(PositiveA, B) 2) -> (icmp eq B 1)
-define i32 @clamp_check_for_no_infinite_loop3(i32 %i) {
-; CHECK-LABEL: @clamp_check_for_no_infinite_loop3(
-; CHECK-NEXT:    [[I2:%.*]] = icmp sgt i32 [[I:%.*]], 1
-; CHECK-NEXT:    [[I3:%.*]] = select i1 [[I2]], i32 [[I]], i32 1
-; CHECK-NEXT:    br i1 true, label [[TRUELABEL:%.*]], label [[FALSELABEL:%.*]]
-; CHECK:       truelabel:
-; CHECK-NEXT:    [[I5:%.*]] = icmp slt i32 [[I3]], 2
-; CHECK-NEXT:    [[I6:%.*]] = select i1 [[I5]], i32 [[I3]], i32 2
-; CHECK-NEXT:    [[I7:%.*]] = shl nuw nsw i32 [[I6]], 2
-; CHECK-NEXT:    ret i32 [[I7]]
-; CHECK:       falselabel:
-; CHECK-NEXT:    ret i32 0
-;
-
-  %i2 = icmp sgt i32 %i, 1
-  %i3 = select i1 %i2, i32 %i, i32 1
-  %i4 = icmp sgt i32 %i3, 0
-  br i1 %i4, label %truelabel, label %falselabel
-
-truelabel: ; %i<=1, %i3>0
-  %i5 = icmp slt i32 %i3, 2
-  %i6 = select i1 %i5, i32 %i3, i32 2
-  %i7 = shl nuw nsw i32 %i6, 2
-  ret i32 %i7
-
-falselabel:
-  ret i32 0
-}
-
 ; The next 3 min tests should canonicalize to the same form...and not infinite loop.
 
 define double @PR31751_umin1(i32 %x) {
diff --git a/llvm/test/Transforms/InstSimplify/cmp_of_min_max.ll b/llvm/test/Transforms/InstSimplify/cmp_of_min_max.ll
index 34c4a15..4726609 100644
--- a/llvm/test/Transforms/InstSimplify/cmp_of_min_max.ll
+++ b/llvm/test/Transforms/InstSimplify/cmp_of_min_max.ll
@@ -3,7 +3,10 @@
 
 define i1 @test_umax1(i32 %n) {
 ; CHECK-LABEL: @test_umax1(
-; CHECK-NEXT:    ret i1 true
+; CHECK-NEXT:    [[C1:%.*]] = icmp ugt i32 [[N:%.*]], 10
+; CHECK-NEXT:    [[S:%.*]] = select i1 [[C1]], i32 [[N]], i32 10
+; CHECK-NEXT:    [[C2:%.*]] = icmp ugt i32 [[S]], 9
+; CHECK-NEXT:    ret i1 [[C2]]
 ;
   %c1 = icmp ugt i32 %n, 10
   %s = select i1 %c1, i32 %n, i32 10
@@ -37,7 +40,10 @@ define i1 @test_umax3(i32 %n) {
 
 define i1 @test_umin1(i32 %n) {
 ; CHECK-LABEL: @test_umin1(
-; CHECK-NEXT:    ret i1 true
+; CHECK-NEXT:    [[C1:%.*]] = icmp ult i32 [[N:%.*]], 10
+; CHECK-NEXT:    [[S:%.*]] = select i1 [[C1]], i32 [[N]], i32 10
+; CHECK-NEXT:    [[C2:%.*]] = icmp ult i32 [[S]], 11
+; CHECK-NEXT:    ret i1 [[C2]]
 ;
   %c1 = icmp ult i32 %n, 10
   %s = select i1 %c1, i32 %n, i32 10
@@ -71,7 +77,10 @@ define i1 @test_umin3(i32 %n) {
 
 define i1 @test_smax1(i32 %n) {
 ; CHECK-LABEL: @test_smax1(
-; CHECK-NEXT:    ret i1 true
+; CHECK-NEXT:    [[C1:%.*]] = icmp sgt i32 [[N:%.*]], -10
+; CHECK-NEXT:    [[S:%.*]] = select i1 [[C1]], i32 [[N]], i32 -10
+; CHECK-NEXT:    [[C2:%.*]] = icmp sgt i32 [[S]], -11
+; CHECK-NEXT:    ret i1 [[C2]]
 ;
   %c1 = icmp sgt i32 %n, -10
   %s = select i1 %c1, i32 %n, i32 -10
@@ -105,7 +114,10 @@ define i1 @test_smax3(i32 %n) {
 
 define i1 @test_smin1(i32 %n) {
 ; CHECK-LABEL: @test_smin1(
-; CHECK-NEXT:    ret i1 true
+; CHECK-NEXT:    [[C1:%.*]] = icmp slt i32 [[N:%.*]], 10
+; CHECK-NEXT:    [[S:%.*]] = select i1 [[C1]], i32 [[N]], i32 10
+; CHECK-NEXT:    [[C2:%.*]] = icmp slt i32 [[S]], 11
+; CHECK-NEXT:    ret i1 [[C2]]
 ;
   %c1 = icmp slt i32 %n, 10
   %s = select i1 %c1, i32 %n, i32 10
-- 
2.7.4