[PATCH] D97047: [Analysis][LoopVectorize] do not try to form reductions of pointers

[Sanjay Patel via Phabricator via llvm-commits]

This revision was automatically updated to reflect the committed changes.
Closed by commit rG5b250a27ec78: [Analysis][LoopVectorize] do not form reductions of pointers (authored by spatel).

Changed prior to commit:
  https://reviews.llvm.org/D97047?vs=324962&id=325044#toc

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D97047/new/

https://reviews.llvm.org/D97047

Files:
  llvm/lib/Analysis/IVDescriptors.cpp
  llvm/test/Transforms/LoopVectorize/reduction-ptr.ll


Index: llvm/test/Transforms/LoopVectorize/reduction-ptr.ll
===================================================================
--- /dev/null
+++ llvm/test/Transforms/LoopVectorize/reduction-ptr.ll
@@ -0,0 +1,40 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt < %s  -loop-vectorize -force-vector-width=4 -S | FileCheck %s
+
+target datalayout = "e-m:o-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
+
+; Reductions of pointer types are not supported.
+
+define void @PR49215(i32* %p, i32* %q) {
+; CHECK-LABEL: @PR49215(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    br label [[FOR_BODY:%.*]]
+; CHECK:       for.body:
+; CHECK-NEXT:    [[IV:%.*]] = phi i64 [ 0, [[ENTRY:%.*]] ], [ [[IV_NEXT:%.*]], [[FOR_BODY]] ]
+; CHECK-NEXT:    [[G:%.*]] = phi i32* [ [[P:%.*]], [[ENTRY]] ], [ [[UMIN:%.*]], [[FOR_BODY]] ]
+; CHECK-NEXT:    [[CMP2:%.*]] = icmp ult i32* [[Q:%.*]], [[G]]
+; CHECK-NEXT:    [[UMIN]] = select i1 [[CMP2]], i32* [[Q]], i32* [[G]]
+; CHECK-NEXT:    [[IV_NEXT]] = add nuw nsw i64 [[IV]], 1
+; CHECK-NEXT:    [[EXITCOND:%.*]] = icmp eq i64 [[IV_NEXT]], undef
+; CHECK-NEXT:    br i1 [[EXITCOND]], label [[LOOPEXIT:%.*]], label [[FOR_BODY]]
+; CHECK:       loopexit:
+; CHECK-NEXT:    [[UMIN_LCSSA:%.*]] = phi i32* [ [[UMIN]], [[FOR_BODY]] ]
+; CHECK-NEXT:    [[PHI_CAST:%.*]] = ptrtoint i32* [[UMIN_LCSSA]] to i64
+; CHECK-NEXT:    ret void
+;
+entry:
+  br label %for.body
+
+for.body:
+  %iv = phi i64 [ 0, %entry ], [ %iv.next, %for.body ]
+  %g = phi i32* [ %p, %entry ], [ %umin, %for.body ]
+  %cmp2 = icmp ult i32* %q, %g
+  %umin = select i1 %cmp2, i32* %q, i32* %g
+  %iv.next = add nuw nsw i64 %iv, 1
+  %exitcond = icmp eq i64 %iv.next, undef
+  br i1 %exitcond, label %loopexit, label %for.body
+
+loopexit:
+  %phi.cast = ptrtoint i32* %umin to i64
+  ret void
+}
Index: llvm/lib/Analysis/IVDescriptors.cpp
===================================================================
--- llvm/lib/Analysis/IVDescriptors.cpp
+++ llvm/lib/Analysis/IVDescriptors.cpp
@@ -243,11 +243,14 @@
   if (RecurrenceType->isFloatingPointTy()) {
     if (!isFloatingPointRecurrenceKind(Kind))
       return false;
-  } else {
+  } else if (RecurrenceType->isIntegerTy()) {
     if (!isIntegerRecurrenceKind(Kind))
       return false;
     if (isArithmeticRecurrenceKind(Kind))
       Start = lookThroughAnd(Phi, RecurrenceType, VisitedInsts, CastInsts);
+  } else {
+    // Pointer min/max may exist, but it is not supported as a reduction op.
+    return false;
   }
 
   Worklist.push_back(Start);


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