[PATCH] D149415: [ValueTracking] Add logic for `isKnownNonZero(umax X, Y)`

[Noah Goldstein via Phabricator via llvm-commits]

goldstein.w.n created this revision.
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`(umax X, Y) != 0` -> `X != 0 || Y != 0`

Alive2 Link:

  https://alive2.llvm.org/ce/z/_Z9AUT


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D149415

Files:
  llvm/lib/Analysis/ValueTracking.cpp
  llvm/test/Analysis/ValueTracking/known-non-zero.ll
  llvm/test/Transforms/LoopVectorize/interleaved-accesses.ll


Index: llvm/test/Transforms/LoopVectorize/interleaved-accesses.ll
===================================================================
--- llvm/test/Transforms/LoopVectorize/interleaved-accesses.ll
+++ llvm/test/Transforms/LoopVectorize/interleaved-accesses.ll
@@ -483,10 +483,10 @@
 ; CHECK-LABEL: @even_load_dynamic_tc(
 ; CHECK-NEXT:  entry:
 ; CHECK-NEXT:    [[UMAX:%.*]] = call i64 @llvm.umax.i64(i64 [[N:%.*]], i64 2)
-; CHECK-NEXT:    [[TMP0:%.*]] = add i64 [[UMAX]], -1
-; CHECK-NEXT:    [[MIN_ITERS_CHECK:%.*]] = icmp ult i64 [[TMP0]], 8
+; CHECK-NEXT:    [[MIN_ITERS_CHECK:%.*]] = icmp ult i64 [[UMAX]], 9
 ; CHECK-NEXT:    br i1 [[MIN_ITERS_CHECK]], label [[SCALAR_PH:%.*]], label [[VECTOR_PH:%.*]]
 ; CHECK:       vector.ph:
+; CHECK-NEXT:    [[TMP0:%.*]] = add i64 [[UMAX]], -1
 ; CHECK-NEXT:    [[TMP1:%.*]] = lshr i64 [[TMP0]], 1
 ; CHECK-NEXT:    [[TMP2:%.*]] = add nuw i64 [[TMP1]], 1
 ; CHECK-NEXT:    [[N_MOD_VF:%.*]] = and i64 [[TMP2]], 3
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
@@ -886,10 +886,7 @@
 ; CHECK-LABEL: @umax_nonzero(
 ; CHECK-NEXT:    [[X_NZ:%.*]] = icmp ne i8 [[XX:%.*]], 0
 ; CHECK-NEXT:    call void @llvm.assume(i1 [[X_NZ]])
-; CHECK-NEXT:    [[X:%.*]] = call i8 @llvm.umax.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_nz = icmp ne i8 %xx, 0
   call void @llvm.assume(i1 %x_nz)
Index: llvm/lib/Analysis/ValueTracking.cpp
===================================================================
--- llvm/lib/Analysis/ValueTracking.cpp
+++ llvm/lib/Analysis/ValueTracking.cpp
@@ -2920,6 +2920,7 @@
                          II->getArgOperand(1)))
           return true;
         break;
+      case Intrinsic::umax:
       case Intrinsic::uadd_sat:
         if (isKnownNonZero(II->getArgOperand(0), DemandedElts, Depth, Q) ||
             isKnownNonZero(II->getArgOperand(1), DemandedElts, Depth, Q))


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