Fix PR18165: LSR must avoid scaling factors that exceed the limit on truncated use.

Patch by Michael Zolotukhin!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@202273 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Transforms/Scalar/LoopStrengthReduce.cpp b/lib/Transforms/Scalar/LoopStrengthReduce.cpp
index b25943011f38b9fe9410b5f02d6448b05081ace4..093352ba572069324a5be36fc08ab4feb825b4bc 100644 (file)
--- a/lib/Transforms/Scalar/LoopStrengthReduce.cpp
+++ b/lib/Transforms/Scalar/LoopStrengthReduce.cpp
@@ -3389,6 +3389,10 @@ void LSRInstance::GenerateICmpZeroScales(LSRUse &LU, unsigned LUIdx,
     int64_t NewBaseOffset = (uint64_t)Base.BaseOffset * Factor;
     if (NewBaseOffset / Factor != Base.BaseOffset)
       continue;
+    // If the offset will be truncated at this use, check that it is in bounds.
+    if (!IntTy->isPointerTy() &&
+        !ConstantInt::isValueValidForType(IntTy, NewBaseOffset))
+      continue;
 
     // Check that multiplying with the use offset doesn't overflow.
     int64_t Offset = LU.MinOffset;
@@ -3397,6 +3401,10 @@ void LSRInstance::GenerateICmpZeroScales(LSRUse &LU, unsigned LUIdx,
     Offset = (uint64_t)Offset * Factor;
     if (Offset / Factor != LU.MinOffset)
       continue;
+    // If the offset will be truncated at this use, check that it is in bounds.
+    if (!IntTy->isPointerTy() &&
+        !ConstantInt::isValueValidForType(IntTy, Offset))
+      continue;
 
     Formula F = Base;
     F.BaseOffset = NewBaseOffset;
@@ -3431,6 +3439,10 @@ void LSRInstance::GenerateICmpZeroScales(LSRUse &LU, unsigned LUIdx,
       F.UnfoldedOffset = (uint64_t)F.UnfoldedOffset * Factor;
       if (F.UnfoldedOffset / Factor != Base.UnfoldedOffset)
         continue;
+      // If the offset will be truncated, check that it is in bounds.
+      if (!IntTy->isPointerTy() &&
+          !ConstantInt::isValueValidForType(IntTy, F.UnfoldedOffset))
+        continue;
     }
 
     // If we make it here and it's legal, add it.

diff --git a/test/Transforms/LoopStrengthReduce/pr18165.ll b/test/Transforms/LoopStrengthReduce/pr18165.ll
new file mode 100644 (file)
index 0000000..c38d6a6
--- /dev/null
+++ b/test/Transforms/LoopStrengthReduce/pr18165.ll
@@ -0,0 +1,88 @@
+; RUN: opt < %s -loop-reduce -S | FileCheck %s
+target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-apple-macosx10.9.0"
+
+; LSR shouldn't reuse IV if the resultant offset is not valid for the operand type.
+; CHECK-NOT: trunc i32 %.ph to i8
+
+%struct.anon = type { i32, i32, i32 }
+
+@c = global i32 1, align 4
+@.str = private unnamed_addr constant [4 x i8] c"%d\0A\00", align 1
+@b = common global i32 0, align 4
+@a = common global %struct.anon zeroinitializer, align 4
+@e = common global %struct.anon zeroinitializer, align 4
+@d = common global i32 0, align 4
+@f = common global i32 0, align 4
+@g = common global i32 0, align 4
+@h = common global i32 0, align 4
+
+; Function Attrs: nounwind optsize ssp uwtable
+define i32 @main() #0 {
+entry:
+  %0 = load i32* getelementptr inbounds (%struct.anon* @a, i64 0, i32 0), align 4, !tbaa !1
+  %tobool7.i = icmp eq i32 %0, 0
+  %.promoted.i = load i32* getelementptr inbounds (%struct.anon* @a, i64 0, i32 2), align 4, !tbaa !6
+  %f.promoted.i = load i32* @f, align 4, !tbaa !7
+  br label %for.body6.i.outer
+
+for.body6.i.outer:                                ; preds = %entry, %lor.end.i
+  %.ph = phi i32 [ %add.i, %lor.end.i ], [ 0, %entry ]
+  %or1512.i.ph = phi i32 [ %or15.i, %lor.end.i ], [ %f.promoted.i, %entry ]
+  %or1410.i.ph = phi i32 [ %or14.i, %lor.end.i ], [ %.promoted.i, %entry ]
+  %p.addr.16.i.ph = phi i8 [ %inc10.i, %lor.end.i ], [ -128, %entry ]
+  br i1 %tobool7.i, label %if.end9.i, label %lbl.loopexit.i
+
+lbl.loopexit.i:                                   ; preds = %for.body6.i.outer, %lbl.loopexit.i
+  br label %lbl.loopexit.i
+
+if.end9.i:                                        ; preds = %for.body6.i.outer
+  %inc10.i = add i8 %p.addr.16.i.ph, 1
+  %tobool12.i = icmp eq i8 %p.addr.16.i.ph, 0
+  br i1 %tobool12.i, label %lor.rhs.i, label %lor.end.i
+
+lor.rhs.i:                                        ; preds = %if.end9.i
+  %1 = load i32* @b, align 4, !tbaa !7
+  %dec.i = add nsw i32 %1, -1
+  store i32 %dec.i, i32* @b, align 4, !tbaa !7
+  %tobool13.i = icmp ne i32 %1, 0
+  br label %lor.end.i
+
+lor.end.i:                                        ; preds = %lor.rhs.i, %if.end9.i
+  %2 = phi i1 [ true, %if.end9.i ], [ %tobool13.i, %lor.rhs.i ]
+  %lor.ext.i = zext i1 %2 to i32
+  %or14.i = or i32 %lor.ext.i, %or1410.i.ph
+  %or15.i = or i32 %or14.i, %or1512.i.ph
+  %add.i = add nsw i32 %.ph, 2
+  %cmp.i = icmp slt i32 %add.i, 21
+  br i1 %cmp.i, label %for.body6.i.outer, label %fn1.exit
+
+fn1.exit:                                         ; preds = %lor.end.i
+  store i32 0, i32* @g, align 4, !tbaa !7
+  store i32 %or14.i, i32* getelementptr inbounds (%struct.anon* @a, i64 0, i32 2), align 4, !tbaa !6
+  store i32 %or15.i, i32* @f, align 4, !tbaa !7
+  store i32 %add.i, i32* getelementptr inbounds (%struct.anon* @e, i64 0, i32 1), align 4, !tbaa !8
+  store i32 0, i32* @h, align 4, !tbaa !7
+  %3 = load i32* @b, align 4, !tbaa !7
+  %call1 = tail call i32 (i8*, ...)* @printf(i8* getelementptr inbounds ([4 x i8]* @.str, i64 0, i64 0), i32 %3) #2
+  ret i32 0
+}
+
+; Function Attrs: nounwind optsize
+declare i32 @printf(i8* nocapture readonly, ...) #1
+
+attributes #0 = { nounwind optsize ssp uwtable "less-precise-fpmad"="false" "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "unsafe-fp-math"="false" "use-soft-float"="false" }
+attributes #1 = { nounwind optsize "less-precise-fpmad"="false" "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "unsafe-fp-math"="false" "use-soft-float"="false" }
+attributes #2 = { nounwind optsize }
+
+!llvm.ident = !{!0}
+
+!0 = metadata !{metadata !"clang version 3.5 "}
+!1 = metadata !{metadata !2, metadata !3, i64 0}
+!2 = metadata !{metadata !"", metadata !3, i64 0, metadata !3, i64 4, metadata !3, i64 8}
+!3 = metadata !{metadata !"int", metadata !4, i64 0}
+!4 = metadata !{metadata !"omnipotent char", metadata !5, i64 0}
+!5 = metadata !{metadata !"Simple C/C++ TBAA"}
+!6 = metadata !{metadata !2, metadata !3, i64 8}
+!7 = metadata !{metadata !3, metadata !3, i64 0}
+!8 = metadata !{metadata !2, metadata !3, i64 4}