[InstCombine] InstCombine and InstSimplify for minimum and maximum

Summary: Depends on D52765

Reviewers: aheejin, dschuff

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D52766

llvm-svn: 344799

1 files changed, 22 insertions, 5 deletions

diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
index 6d2ac2274de..116b11386f0 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
@@ -2020,7 +2020,9 @@ Instruction *InstCombiner::visitCallInst(CallInst &CI) {
   }
 
   case Intrinsic::minnum:
-  case Intrinsic::maxnum: {
+  case Intrinsic::maxnum:
+  case Intrinsic::minimum:
+  case Intrinsic::maximum: {
     Value *Arg0 = II->getArgOperand(0);
     Value *Arg1 = II->getArgOperand(1);
     // Canonicalize constants to the RHS.
@@ -2034,10 +2036,25 @@ Instruction *InstCombiner::visitCallInst(CallInst &CI) {
     if (match(Arg0, m_FNeg(m_Value(X))) && match(Arg1, m_FNeg(m_Value(Y))) &&
         (Arg0->hasOneUse() || Arg1->hasOneUse())) {
       // If both operands are negated, invert the call and negate the result:
-      // minnum(-X, -Y) --> -(maxnum(X, Y))
-      // maxnum(-X, -Y) --> -(minnum(X, Y))
-      Intrinsic::ID NewIID = II->getIntrinsicID() == Intrinsic::maxnum ?
-          Intrinsic::minnum : Intrinsic::maxnum;
+      // min(-X, -Y) --> -(max(X, Y))
+      // max(-X, -Y) --> -(min(X, Y))
+      Intrinsic::ID NewIID;
+      switch (II->getIntrinsicID()) {
+      case Intrinsic::maxnum:
+        NewIID = Intrinsic::minnum;
+        break;
+      case Intrinsic::minnum:
+        NewIID = Intrinsic::maxnum;
+        break;
+      case Intrinsic::maximum:
+        NewIID = Intrinsic::minimum;
+        break;
+      case Intrinsic::minimum:
+        NewIID = Intrinsic::maximum;
+        break;
+      default:
+        llvm_unreachable("unexpected intrinsic ID");
+      }
       Value *NewCall = Builder.CreateBinaryIntrinsic(NewIID, X, Y, II);
       Instruction *FNeg = BinaryOperator::CreateFNeg(NewCall);
       FNeg->copyIRFlags(II);