[llvm] eee0ded - [InstCombine] add min/max intrinsics as freely invertible candidates

[Sanjay Patel via llvm-commits]

Author: Sanjay Patel
Date: 2021-08-19T08:41:38-04:00
New Revision: eee0ded3371f549ba6df045c0348e8e32d576df9

URL: https://github.com/llvm/llvm-project/commit/eee0ded3371f549ba6df045c0348e8e32d576df9
DIFF: https://github.com/llvm/llvm-project/commit/eee0ded3371f549ba6df045c0348e8e32d576df9.diff

LOG: [InstCombine] add min/max intrinsics as freely invertible candidates

In the optimized test, we are able to peak through the
min/max that has 2 min/max operands and invert them all:
https://alive2.llvm.org/ce/z/7gYMN5

Added: 
    

Modified: 
    llvm/include/llvm/Transforms/InstCombine/InstCombiner.h
    llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
    llvm/test/Transforms/InstCombine/minmax-intrinsics.ll

Removed: 
    


################################################################################
diff  --git a/llvm/include/llvm/Transforms/InstCombine/InstCombiner.h b/llvm/include/llvm/Transforms/InstCombine/InstCombiner.h
index ba0d41f9b748..3f13df7b76b4 100644
--- a/llvm/include/llvm/Transforms/InstCombine/InstCombiner.h
+++ b/llvm/include/llvm/Transforms/InstCombine/InstCombiner.h
@@ -259,6 +259,12 @@ class LLVM_LIBRARY_VISIBILITY InstCombiner {
                        m_Not(PatternMatch::m_Value()))))
       return WillInvertAllUses;
 
+    // Min/max may be in the form of intrinsics, so handle those identically
+    // to select patterns.
+    if (match(V, m_MaxOrMin(m_Not(PatternMatch::m_Value()),
+                            m_Not(PatternMatch::m_Value()))))
+      return WillInvertAllUses;
+
     return false;
   }
 

diff  --git a/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp b/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
index 46d874885457..5c05bc57a0cf 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
@@ -3577,9 +3577,13 @@ Instruction *InstCombinerImpl::visitXor(BinaryOperator &I) {
   // ~max(~X, Y) --> min(X, ~Y)
   auto *II = dyn_cast<IntrinsicInst>(Op0);
   if (II && II->hasOneUse() && match(Op1, m_AllOnes())) {
-    if (match(Op0, m_MaxOrMin(m_Not(m_Value(X)), m_Not(m_Value(Y))))) {
+    if (match(Op0, m_MaxOrMin(m_Value(X), m_Value(Y))) &&
+        isFreeToInvert(X, X->hasOneUse()) &&
+        isFreeToInvert(Y, Y->hasOneUse())) {
       Intrinsic::ID InvID = getInverseMinMaxIntrinsic(II->getIntrinsicID());
-      Value *InvMaxMin = Builder.CreateBinaryIntrinsic(InvID, X, Y);
+      Value *NotX = Builder.CreateNot(X);
+      Value *NotY = Builder.CreateNot(Y);
+      Value *InvMaxMin = Builder.CreateBinaryIntrinsic(InvID, NotX, NotY);
       return replaceInstUsesWith(I, InvMaxMin);
     }
     if (match(Op0, m_c_MaxOrMin(m_Not(m_Value(X)), m_Value(Y)))) {

diff  --git a/llvm/test/Transforms/InstCombine/minmax-intrinsics.ll b/llvm/test/Transforms/InstCombine/minmax-intrinsics.ll
index 09e0545f107e..7816d5d6a32e 100644
--- a/llvm/test/Transforms/InstCombine/minmax-intrinsics.ll
+++ b/llvm/test/Transforms/InstCombine/minmax-intrinsics.ll
@@ -1158,7 +1158,7 @@ define i8 @freeToInvert(i8 %x, i8 %y, i8 %z) {
 ; CHECK-NEXT:    call void @use(i8 [[NY]])
 ; CHECK-NEXT:    call void @use(i8 [[NZ]])
 ; CHECK-NEXT:    [[TMP1:%.*]] = call i8 @llvm.umin.i8(i8 [[X]], i8 [[Y]])
-; CHECK-NEXT:    [[TMP2:%.*]] = call i8 @llvm.smax.i8(i8 [[Z]], i8 [[TMP1]])
+; CHECK-NEXT:    [[TMP2:%.*]] = call i8 @llvm.smax.i8(i8 [[TMP1]], i8 [[Z]])
 ; CHECK-NEXT:    ret i8 [[TMP2]]
 ;
   %nx = xor i8 %x, -1
@@ -1266,11 +1266,10 @@ define i8 @freeToInvert_two_minmax_ops(i8 %x, i8 %y, i8 %z, i8 %w) {
 ; CHECK-NEXT:    call void @use(i8 [[NY]])
 ; CHECK-NEXT:    call void @use(i8 [[NZ]])
 ; CHECK-NEXT:    call void @use(i8 [[NW]])
-; CHECK-NEXT:    [[M1:%.*]] = call i8 @llvm.umax.i8(i8 [[NX]], i8 [[NY]])
-; CHECK-NEXT:    [[M2:%.*]] = call i8 @llvm.smax.i8(i8 [[NW]], i8 [[NZ]])
-; CHECK-NEXT:    [[M3:%.*]] = call i8 @llvm.smin.i8(i8 [[M1]], i8 [[M2]])
-; CHECK-NEXT:    [[NOT:%.*]] = xor i8 [[M3]], -1
-; CHECK-NEXT:    ret i8 [[NOT]]
+; CHECK-NEXT:    [[TMP1:%.*]] = call i8 @llvm.umin.i8(i8 [[X]], i8 [[Y]])
+; CHECK-NEXT:    [[TMP2:%.*]] = call i8 @llvm.smin.i8(i8 [[W]], i8 [[Z]])
+; CHECK-NEXT:    [[TMP3:%.*]] = call i8 @llvm.smax.i8(i8 [[TMP1]], i8 [[TMP2]])
+; CHECK-NEXT:    ret i8 [[TMP3]]
 ;
   %nx = xor i8 %x, -1
   %ny = xor i8 %y, -1