[PATCH] D34879: [LoopInterchange] Skip zext instructions when looking for induction var.

[Florian Hahn via Phabricator via llvm-commits]

fhahn updated this revision to Diff 112705.
fhahn added a comment.

rebased


https://reviews.llvm.org/D34879

Files:
  lib/Transforms/Scalar/LoopInterchange.cpp
  test/Transforms/LoopInterchange/interchange-insts-between-indvar.ll


Index: test/Transforms/LoopInterchange/interchange-insts-between-indvar.ll
===================================================================
--- /dev/null
+++ test/Transforms/LoopInterchange/interchange-insts-between-indvar.ll
@@ -0,0 +1,80 @@
+; RUN: opt < %s -basicaa -loop-interchange -S | FileCheck %s
+
+ at A10 = local_unnamed_addr global [3 x [3 x i32]] zeroinitializer, align 16
+
+;; Test to make sure we can handle zext intructions introduced by
+;; IndVarSimplify.
+;;
+;;  for (int i = 0; i < 2; ++i)
+;;    for(int j = 0; j < n; ++j) {
+;;      A[j][i] = i;
+;;    }
+
+ at A11 = local_unnamed_addr global [3 x [3 x i32]] zeroinitializer, align 16
+
+define void @interchange_11(i32 %n) {
+entry:
+  br label %for.cond1.preheader
+
+for.cond.loopexit:                                ; preds = %for.body4
+  %exitcond28 = icmp ne i64 %indvars.iv.next27, 2
+  br i1 %exitcond28, label %for.cond1.preheader, label %for.cond.cleanup
+
+for.cond1.preheader:                              ; preds = %for.cond.loopexit, %entry
+  %indvars.iv26 = phi i64 [ 0, %entry ], [ %indvars.iv.next27, %for.cond.loopexit ]
+  %indvars.iv.next27 = add nuw nsw i64 %indvars.iv26, 1
+  br label %for.body4
+
+for.cond.cleanup:                                 ; preds = %for.cond.loopexit
+  ret void
+
+for.body4:                                        ; preds = %for.body4, %for.cond1.preheader
+  %indvars.iv = phi i64 [ 0, %for.cond1.preheader ], [ %indvars.iv.next, %for.body4 ]
+  %arrayidx6 = getelementptr inbounds [3 x [3 x i32]], [3 x [3 x i32]]* @A10, i64 0, i64 %indvars.iv, i64 %indvars.iv26
+  %tmp = trunc i64 %indvars.iv26 to i32
+  store i32 %tmp, i32* %arrayidx6, align 4
+  %arrayidx10 = getelementptr inbounds [3 x [3 x i32]], [3 x [3 x i32]]* @A10, i64 0, i64 %indvars.iv, i64 %indvars.iv.next27
+  %tmp1 = trunc i64 %indvars.iv to i32
+  store i32 %tmp1, i32* %arrayidx10, align 4
+  %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
+  %n.wide = zext i32 %n to i64
+  %exitcond = icmp ne i64 %indvars.iv.next, %n.wide
+  br i1 %exitcond, label %for.body4, label %for.cond.loopexit
+}
+
+; CHECK-LABEL: @interchange_11
+; CHECK: entry:
+; CHECK:   br label %for.body4.preheader
+
+; CHECK: for.cond1.preheader.preheader:
+; CHECK:   br label %for.cond1.preheader
+
+; CHECK: for.cond.loopexit:
+; CHECK:   %exitcond28 = icmp ne i64 %indvars.iv.next27, 2
+; CHECK:   br i1 %exitcond28, label %for.cond1.preheader, label %for.body4.split
+
+; CHECK: for.cond1.preheader:
+; CHECK:   %indvars.iv26 = phi i64 [ %indvars.iv.next27, %for.cond.loopexit ], [ 0, %for.cond1.preheader.preheader ]
+; CHECK:   %indvars.iv.next27 = add nuw nsw i64 %indvars.iv26, 1
+; CHECK:   br label %for.body4.split1
+
+; CHECK: for.body4.preheader:
+; CHECK:   br label %for.body4
+
+; CHECK: for.cond.cleanup:
+; CHECK:   ret void
+
+; CHECK: for.body4:
+; CHECK:   %indvars.iv = phi i64 [ %indvars.iv.next, %for.body4.split ], [ 0, %for.body4.preheader ]
+; CHECK:   br label %for.cond1.preheader.preheader
+
+; CHECK: for.body4.split1:
+; CHECK:   %arrayidx6 = getelementptr inbounds [3 x [3 x i32]], [3 x [3 x i32]]* @A10, i64 0, i64 %indvars.iv, i64 %indvars.iv26
+; CHECK:   %tmp = trunc i64 %indvars.iv26 to i32
+; CHECK:   store i32 %tmp, i32* %arrayidx6, align 4
+; CHECK:   br label %for.cond.loopexit
+
+; CHECK: for.body4.split:
+; CHECK:   %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
+; CHECK:   %exitcond = icmp ne i64 %indvars.iv.next, %n.wide
+; CHECK:   br i1 %exitcond, label %for.body4, label %for.cond.cleanup
Index: lib/Transforms/Scalar/LoopInterchange.cpp
===================================================================
--- lib/Transforms/Scalar/LoopInterchange.cpp
+++ lib/Transforms/Scalar/LoopInterchange.cpp
@@ -908,7 +908,8 @@
 
   bool FoundInduction = false;
   for (const Instruction &I : reverse(*InnerLoopLatch)) {
-    if (isa<BranchInst>(I) || isa<CmpInst>(I) || isa<TruncInst>(I))
+    if (isa<BranchInst>(I) || isa<CmpInst>(I) || isa<TruncInst>(I) ||
+        isa<ZExtInst>(I))
       continue;
 
     // We found an instruction. If this is not induction variable then it is not


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