[PATCH] D149414: [ValueTracking] Add logic for `isKnownNonZero(sadd.sat X, Y)`

[Noah Goldstein via Phabricator via llvm-commits]

goldstein.w.n created this revision.
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The logic here is the same for `add` so reuse the existing helper
`isNonZeroAdd`

Alive2 Link:

  https://alive2.llvm.org/ce/z/mhKvC5


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D149414

Files:
  llvm/lib/Analysis/ValueTracking.cpp
  llvm/test/Analysis/ValueTracking/known-non-zero.ll


Index: llvm/test/Analysis/ValueTracking/known-non-zero.ll
===================================================================
--- llvm/test/Analysis/ValueTracking/known-non-zero.ll
+++ llvm/test/Analysis/ValueTracking/known-non-zero.ll
@@ -849,10 +849,7 @@
 ; CHECK-NEXT:    [[Y_POS:%.*]] = icmp sge i8 [[YY:%.*]], 0
 ; CHECK-NEXT:    call void @llvm.assume(i1 [[X_STRICT_POS]])
 ; CHECK-NEXT:    call void @llvm.assume(i1 [[Y_POS]])
-; CHECK-NEXT:    [[X:%.*]] = call i8 @llvm.sadd.sat.i8(i8 [[XX]], i8 [[YY]])
-; CHECK-NEXT:    [[Z:%.*]] = or i8 [[X]], [[IND:%.*]]
-; CHECK-NEXT:    [[R:%.*]] = icmp eq i8 [[Z]], 0
-; CHECK-NEXT:    ret i1 [[R]]
+; CHECK-NEXT:    ret i1 false
 ;
   %x_strict_pos = icmp sgt i8 %xx, 0
   %y_pos = icmp sge i8 %yy, 0
Index: llvm/lib/Analysis/ValueTracking.cpp
===================================================================
--- llvm/lib/Analysis/ValueTracking.cpp
+++ llvm/lib/Analysis/ValueTracking.cpp
@@ -2915,6 +2915,11 @@
         std::optional<bool> ugt = KnownBits::ugt(XKnown, YKnown);
         return ugt && *ugt;
       }
+      case Intrinsic::sadd_sat:
+        if (isNonZeroAdd(DemandedElts, Depth, Q, BitWidth, II->getArgOperand(0),
+                         II->getArgOperand(1)))
+          return true;
+        break;
       case Intrinsic::uadd_sat:
         if (isKnownNonZero(II->getArgOperand(0), DemandedElts, Depth, Q) ||
             isKnownNonZero(II->getArgOperand(1), DemandedElts, Depth, Q))


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