[PATCH] D119690: [InstCombine] Update predicate when canonicalizing comparisons in canonicalizeClampLike.

[Ricky Zhou via Phabricator via llvm-commits]

rickyz updated this revision to Diff 425152.
rickyz marked an inline comment as done.
rickyz added a comment.

Rebase, add assert on Pred1.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D119690/new/

https://reviews.llvm.org/D119690

Files:
  llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
  llvm/test/Transforms/InstCombine/canonicalize-clamp-like-pattern-between-negative-and-positive-thresholds.ll


Index: llvm/test/Transforms/InstCombine/canonicalize-clamp-like-pattern-between-negative-and-positive-thresholds.ll
===================================================================
--- llvm/test/Transforms/InstCombine/canonicalize-clamp-like-pattern-between-negative-and-positive-thresholds.ll
+++ llvm/test/Transforms/InstCombine/canonicalize-clamp-like-pattern-between-negative-and-positive-thresholds.ll
@@ -189,10 +189,10 @@
 ; FIXME: This is incorrect, see PR53252.
 define i32 @n10_ugt_slt(i32 %x, i32 %replacement_low, i32 %replacement_high) {
 ; CHECK-LABEL: @n10_ugt_slt(
-; CHECK-NEXT:    [[TMP1:%.*]] = icmp slt i32 [[X:%.*]], 0
-; CHECK-NEXT:    [[TMP2:%.*]] = icmp sgt i32 [[X]], 128
-; CHECK-NEXT:    [[TMP3:%.*]] = select i1 [[TMP1]], i32 [[REPLACEMENT_LOW:%.*]], i32 [[X]]
-; CHECK-NEXT:    [[R:%.*]] = select i1 [[TMP2]], i32 [[REPLACEMENT_HIGH:%.*]], i32 [[TMP3]]
+; CHECK-NEXT:    [[T0:%.*]] = icmp slt i32 [[X:%.*]], 0
+; CHECK-NEXT:    [[T1:%.*]] = select i1 [[T0]], i32 [[REPLACEMENT_LOW:%.*]], i32 [[REPLACEMENT_HIGH:%.*]]
+; CHECK-NEXT:    [[T2:%.*]] = icmp ugt i32 [[X]], 128
+; CHECK-NEXT:    [[R:%.*]] = select i1 [[T2]], i32 [[X]], i32 [[T1]]
 ; CHECK-NEXT:    ret i32 [[R]]
 ;
   %t0 = icmp slt i32 %x, 0
Index: llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
===================================================================
--- llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
+++ llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
@@ -1312,6 +1312,7 @@
                    ICmpInst::Predicate::ICMP_NE,
                    APInt::getAllOnes(C0->getType()->getScalarSizeInBits()))))
       return nullptr; // Can't do, have all-ones element[s].
+    Pred0 = ICmpInst::getFlippedStrictnessPredicate(Pred0);
     C0 = InstCombiner::AddOne(C0);
     break;
   default:
@@ -1377,15 +1378,22 @@
   case ICmpInst::Predicate::ICMP_SGE:
     // Also non-canonical, but here we don't need to change C2,
     // so we don't have any restrictions on C2, so we can just handle it.
+    Pred1 = ICmpInst::Predicate::ICMP_SLT;
     std::swap(ReplacementLow, ReplacementHigh);
     break;
   default:
     return nullptr; // Unknown predicate.
   }
+  assert(Pred1 == ICmpInst::Predicate::ICMP_SLT &&
+         "Unexpected predicate type.");
 
   // The thresholds of this clamp-like pattern.
   auto *ThresholdLowIncl = ConstantExpr::getNeg(C1);
   auto *ThresholdHighExcl = ConstantExpr::getSub(C0, C1);
+
+  assert((Pred0 == ICmpInst::Predicate::ICMP_ULT ||
+          Pred0 == ICmpInst::Predicate::ICMP_UGE) &&
+         "Unexpected predicate type.");
   if (Pred0 == ICmpInst::Predicate::ICMP_UGE)
     std::swap(ThresholdLowIncl, ThresholdHighExcl);
 


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