[PATCH] D61794: [LVI][CVP] Add support for abs/nabs select pattern flavor

[Nikita Popov via Phabricator via llvm-commits]

nikic created this revision.
nikic added reviewers: reames, spatel, lebedev.ri.
Herald added subscribers: llvm-commits, hiraditya.
Herald added a project: LLVM.

Based on ConstantRange support added in D61084 <https://reviews.llvm.org/D61084>, we can now handle abs and nabs select pattern flavors in LVI.


Repository:
  rL LLVM

https://reviews.llvm.org/D61794

Files:
  llvm/lib/Analysis/LazyValueInfo.cpp
  llvm/test/Transforms/CorrelatedValuePropagation/basic.ll


Index: llvm/test/Transforms/CorrelatedValuePropagation/basic.ll
===================================================================
--- llvm/test/Transforms/CorrelatedValuePropagation/basic.ll
+++ llvm/test/Transforms/CorrelatedValuePropagation/basic.ll
@@ -633,8 +633,7 @@
 ; CHECK-NEXT:    store i1 true, i1* [[P:%.*]]
 ; CHECK-NEXT:    [[C2:%.*]] = icmp slt i32 [[ABS]], 19
 ; CHECK-NEXT:    store i1 [[C2]], i1* [[P]]
-; CHECK-NEXT:    [[C3:%.*]] = icmp sge i32 [[ABS]], 0
-; CHECK-NEXT:    store i1 [[C3]], i1* [[P]]
+; CHECK-NEXT:    store i1 true, i1* [[P]]
 ; CHECK-NEXT:    [[C4:%.*]] = icmp sge i32 [[ABS]], 1
 ; CHECK-NEXT:    store i1 [[C4]], i1* [[P]]
 ; CHECK-NEXT:    br label [[EXIT]]
@@ -684,8 +683,7 @@
 ; CHECK-NEXT:    store i1 true, i1* [[P:%.*]]
 ; CHECK-NEXT:    [[C2:%.*]] = icmp slt i32 [[ABS]], 19
 ; CHECK-NEXT:    store i1 [[C2]], i1* [[P]]
-; CHECK-NEXT:    [[C3:%.*]] = icmp sge i32 [[ABS]], 0
-; CHECK-NEXT:    store i1 [[C3]], i1* [[P]]
+; CHECK-NEXT:    store i1 true, i1* [[P]]
 ; CHECK-NEXT:    [[C4:%.*]] = icmp sge i32 [[ABS]], 1
 ; CHECK-NEXT:    store i1 [[C4]], i1* [[P]]
 ; CHECK-NEXT:    br label [[EXIT]]
@@ -735,8 +733,7 @@
 ; CHECK-NEXT:    store i1 true, i1* [[P:%.*]]
 ; CHECK-NEXT:    [[C2:%.*]] = icmp sgt i32 [[NABS]], -19
 ; CHECK-NEXT:    store i1 [[C2]], i1* [[P]]
-; CHECK-NEXT:    [[C3:%.*]] = icmp sle i32 [[NABS]], 0
-; CHECK-NEXT:    store i1 [[C3]], i1* [[P]]
+; CHECK-NEXT:    store i1 true, i1* [[P]]
 ; CHECK-NEXT:    [[C4:%.*]] = icmp sle i32 [[NABS]], -1
 ; CHECK-NEXT:    store i1 [[C4]], i1* [[P]]
 ; CHECK-NEXT:    br label [[EXIT]]
@@ -786,8 +783,7 @@
 ; CHECK-NEXT:    store i1 true, i1* [[P:%.*]]
 ; CHECK-NEXT:    [[C2:%.*]] = icmp sgt i32 [[NABS]], -19
 ; CHECK-NEXT:    store i1 [[C2]], i1* [[P]]
-; CHECK-NEXT:    [[C3:%.*]] = icmp sle i32 [[NABS]], 0
-; CHECK-NEXT:    store i1 [[C3]], i1* [[P]]
+; CHECK-NEXT:    store i1 true, i1* [[P]]
 ; CHECK-NEXT:    [[C4:%.*]] = icmp sle i32 [[NABS]], -1
 ; CHECK-NEXT:    store i1 [[C4]], i1* [[P]]
 ; CHECK-NEXT:    br label [[EXIT]]
Index: llvm/lib/Analysis/LazyValueInfo.cpp
===================================================================
--- llvm/lib/Analysis/LazyValueInfo.cpp
+++ llvm/lib/Analysis/LazyValueInfo.cpp
@@ -893,7 +893,28 @@
       return true;
     }
 
-    // TODO: ABS, NABS from the SelectPatternResult
+    if (SPR.Flavor == SPF_ABS) {
+      if (LHS == SI->getTrueValue()) {
+        BBLV = ValueLatticeElement::getRange(TrueCR.abs());
+        return true;
+      }
+      if (LHS == SI->getFalseValue()) {
+        BBLV = ValueLatticeElement::getRange(FalseCR.abs());
+        return true;
+      }
+    }
+
+    if (SPR.Flavor == SPF_NABS) {
+      ConstantRange Zero(APInt::getNullValue(TrueCR.getBitWidth()));
+      if (LHS == SI->getTrueValue()) {
+        BBLV = ValueLatticeElement::getRange(Zero.sub(TrueCR.abs()));
+        return true;
+      }
+      if (LHS == SI->getFalseValue()) {
+        BBLV = ValueLatticeElement::getRange(Zero.sub(FalseCR.abs()));
+        return true;
+      }
+    }
   }
 
   // Can we constrain the facts about the true and false values by using the


-------------- next part --------------
A non-text attachment was scrubbed...
Name: D61794.199035.patch
Type: text/x-patch
Size: 3138 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20190510/8778399c/attachment.bin>