[PATCH] D23686: Improve the LoopAccessAnalysis to handle the different types in the same size

[Jin Lin via llvm-commits]

jinlin updated this revision to Diff 68587.

Repository:
  rL LLVM

https://reviews.llvm.org/D23686

Files:
  lib/Analysis/LoopAccessAnalysis.cpp
  test/Analysis/LoopAccessAnalysis/same_size_different_type.ll

Index: lib/Analysis/LoopAccessAnalysis.cpp
===================================================================
--- lib/Analysis/LoopAccessAnalysis.cpp
+++ lib/Analysis/LoopAccessAnalysis.cpp
@@ -1268,7 +1268,10 @@
   // Write to the same location with the same size.
   // Could be improved to assert type sizes are the same (i32 == float, etc).
   if (Val == 0) {
-    if (ATy == BTy)
+    if (ATy == BTy ||
+       // Handle the case of different types in the smae size
+       (ATy->getPrimitiveSizeInBits() == BTy->getPrimitiveSizeInBits() &&
+        ATy->getPrimitiveSizeInBits() > 0))
       return Dependence::Forward;
     DEBUG(dbgs() << "LAA: Zero dependence difference but different types\n");
     return Dependence::Unknown;
Index: test/Analysis/LoopAccessAnalysis/same_size_different_type.ll
===================================================================
--- test/Analysis/LoopAccessAnalysis/same_size_different_type.ll
+++ test/Analysis/LoopAccessAnalysis/same_size_different_type.ll
@@ -0,0 +1,40 @@
+; RUN: opt -loop-accesses -analyze < %s | FileCheck %s
+;
+; We expect there exist only one anti-dep in this loop.
+;
+;  for (int i=0;i<N;i++) {
+;    b[i] = c[i];
+;    c[i] = 0.0;
+;  }
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+
+ at c = common local_unnamed_addr global [1000 x double] zeroinitializer, align 16
+ at b = common local_unnamed_addr global [1000 x double] zeroinitializer, align 16
+ at a = common local_unnamed_addr global [1000 x double] zeroinitializer, align 16
+
+; Function Attrs: norecurse nounwind uwtable
+define void @foo() local_unnamed_addr {
+; CHECK: Dependences:
+; CHECK-NEXT:   Forward:
+; CHECK-NEXT:      %1 = load i64, i64* %0, align 8 ->
+; CHECK-NEXT:      store double 0.000000e+00, double* %arrayidx, align 8
+entry:
+  br label %for.body
+
+for.cond.cleanup:                                 ; preds = %for.body
+  ret void
+
+for.body:                                         ; preds = %for.body, %entry
+  %indvars.iv = phi i64 [ 0, %entry ], [ %indvars.iv.next, %for.body ]
+  %arrayidx = getelementptr inbounds [1000 x double], [1000 x double]* @c, i64 0, i64 %indvars.iv
+  %0 = bitcast double* %arrayidx to i64*
+  %1 = load i64, i64* %0, align 8
+  %arrayidx2 = getelementptr inbounds [1000 x double], [1000 x double]* @b, i64 0, i64 %indvars.iv
+  %2 = bitcast double* %arrayidx2 to i64*
+  store i64 %1, i64* %2, align 8
+  store double 0.000000e+00, double* %arrayidx, align 8
+  %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
+  %exitcond = icmp eq i64 %indvars.iv.next, 1000
+  br i1 %exitcond, label %for.cond.cleanup, label %for.body
+}


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