[PATCH] D149411: [ValueTracking] Add logic for `isKnownNonZero(sshl.sat/ushl.sat X, Y)`

[Noah Goldstein via Phabricator via llvm-commits]

goldstein.w.n created this revision.
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`(sshl/ushl X, Y) != 0` -> `X != 0`

Alive2 Links

  https://alive2.llvm.org/ce/z/4WLM2p
  https://alive2.llvm.org/ce/z/BHFng4


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D149411

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
@@ -732,10 +732,7 @@
 ; CHECK-LABEL: @sshl_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.sshl.sat.i8(i8 [[XX]], i8 [[Y:%.*]])
-; 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)
@@ -762,10 +759,7 @@
 ; CHECK-LABEL: @ushl_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.ushl.sat.i8(i8 [[XX]], i8 [[Y:%.*]])
-; 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
@@ -2893,6 +2893,8 @@
   case Instruction::Call:
     if (auto *II = dyn_cast<IntrinsicInst>(I)) {
       switch (II->getIntrinsicID()) {
+      case Intrinsic::sshl_sat:
+      case Intrinsic::ushl_sat:
       case Intrinsic::abs:
       case Intrinsic::bitreverse:
       case Intrinsic::bswap:


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