[PATCH] D87160: [SCEV] Recognize min/max intrinsics

[Nikita Popov via Phabricator via llvm-commits]

nikic created this revision.
nikic added reviewers: lebedev.ri, spatel, fhahn, reames.
Herald added subscribers: llvm-commits, javed.absar, hiraditya.
Herald added a project: LLVM.
nikic requested review of this revision.

Recognize umin/umax/smin/smax intrinsics and convert them to the already existing SCEV nodes of the same name.

In the future we'll want SCEVExpander to also produce the intrinsics, but we're not there yet...


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D87160

Files:
  llvm/lib/Analysis/ScalarEvolution.cpp
  llvm/test/Analysis/ScalarEvolution/minmax-intrinsics.ll


Index: llvm/test/Analysis/ScalarEvolution/minmax-intrinsics.ll
===================================================================
--- llvm/test/Analysis/ScalarEvolution/minmax-intrinsics.ll
+++ llvm/test/Analysis/ScalarEvolution/minmax-intrinsics.ll
@@ -11,7 +11,7 @@
 ; CHECK-LABEL: 'umax'
 ; CHECK-NEXT:  Classifying expressions for: @umax
 ; CHECK-NEXT:    %z = call i32 @llvm.umax.i32(i32 %x, i32 %y)
-; CHECK-NEXT:    --> %z U: full-set S: full-set
+; CHECK-NEXT:    --> (%x umax %y) U: full-set S: full-set
 ; CHECK-NEXT:  Determining loop execution counts for: @umax
 ;
   %z = call i32 @llvm.umax.i32(i32 %x, i32 %y)
@@ -22,7 +22,7 @@
 ; CHECK-LABEL: 'umin'
 ; CHECK-NEXT:  Classifying expressions for: @umin
 ; CHECK-NEXT:    %z = call i32 @llvm.umin.i32(i32 %x, i32 %y)
-; CHECK-NEXT:    --> %z U: full-set S: full-set
+; CHECK-NEXT:    --> (%x umin %y) U: full-set S: full-set
 ; CHECK-NEXT:  Determining loop execution counts for: @umin
 ;
   %z = call i32 @llvm.umin.i32(i32 %x, i32 %y)
@@ -33,7 +33,7 @@
 ; CHECK-LABEL: 'smax'
 ; CHECK-NEXT:  Classifying expressions for: @smax
 ; CHECK-NEXT:    %z = call i32 @llvm.smax.i32(i32 %x, i32 %y)
-; CHECK-NEXT:    --> %z U: full-set S: full-set
+; CHECK-NEXT:    --> (%x smax %y) U: full-set S: full-set
 ; CHECK-NEXT:  Determining loop execution counts for: @smax
 ;
   %z = call i32 @llvm.smax.i32(i32 %x, i32 %y)
@@ -44,7 +44,7 @@
 ; CHECK-LABEL: 'smin'
 ; CHECK-NEXT:  Classifying expressions for: @smin
 ; CHECK-NEXT:    %z = call i32 @llvm.smin.i32(i32 %x, i32 %y)
-; CHECK-NEXT:    --> %z U: full-set S: full-set
+; CHECK-NEXT:    --> (%x smin %y) U: full-set S: full-set
 ; CHECK-NEXT:  Determining loop execution counts for: @smin
 ;
   %z = call i32 @llvm.smin.i32(i32 %x, i32 %y)
@@ -55,9 +55,9 @@
 ; CHECK-LABEL: 'clamp'
 ; CHECK-NEXT:  Classifying expressions for: @clamp
 ; CHECK-NEXT:    %y = call i32 @llvm.umax.i32(i32 %x, i32 10)
-; CHECK-NEXT:    --> %y U: full-set S: full-set
+; CHECK-NEXT:    --> (10 umax %x) U: [10,0) S: [10,0)
 ; CHECK-NEXT:    %z = call i32 @llvm.umin.i32(i32 %y, i32 20)
-; CHECK-NEXT:    --> %z U: full-set S: full-set
+; CHECK-NEXT:    --> (20 umin (10 umax %x)) U: [10,21) S: [10,21)
 ; CHECK-NEXT:  Determining loop execution counts for: @clamp
 ;
   %y = call i32 @llvm.umax.i32(i32 %x, i32 10)
Index: llvm/lib/Analysis/ScalarEvolution.cpp
===================================================================
--- llvm/lib/Analysis/ScalarEvolution.cpp
+++ llvm/lib/Analysis/ScalarEvolution.cpp
@@ -6341,6 +6341,25 @@
   case Instruction::Invoke:
     if (Value *RV = cast<CallBase>(U)->getReturnedArgOperand())
       return getSCEV(RV);
+
+    if (auto *II = dyn_cast<IntrinsicInst>(U)) {
+      switch (II->getIntrinsicID()) {
+      case Intrinsic::umax:
+        return getUMaxExpr(getSCEV(II->getArgOperand(0)),
+                           getSCEV(II->getArgOperand(1)));
+      case Intrinsic::umin:
+        return getUMinExpr(getSCEV(II->getArgOperand(0)),
+                           getSCEV(II->getArgOperand(1)));
+      case Intrinsic::smax:
+        return getSMaxExpr(getSCEV(II->getArgOperand(0)),
+                           getSCEV(II->getArgOperand(1)));
+      case Intrinsic::smin:
+        return getSMinExpr(getSCEV(II->getArgOperand(0)),
+                           getSCEV(II->getArgOperand(1)));
+      default:
+        break;
+      }
+    }
     break;
   }
 


-------------- next part --------------
A non-text attachment was scrubbed...
Name: D87160.290016.patch
Type: text/x-patch
Size: 3395 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20200904/c4bffc99/attachment.bin>