[PATCH] D64869: [SCEV] get more accurate range for AddExpr with NW flag

[ChenZheng via Phabricator via llvm-commits]

shchenz updated this revision to Diff 234678.

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D64869/new/

https://reviews.llvm.org/D64869

Files:
  llvm/include/llvm/IR/Operator.h
  llvm/lib/Analysis/ScalarEvolution.cpp
  llvm/test/Analysis/ScalarEvolution/range_nw_flag.ll
  llvm/test/Transforms/IRCE/ranges_of_different_types.ll


Index: llvm/test/Transforms/IRCE/ranges_of_different_types.ll
===================================================================
--- llvm/test/Transforms/IRCE/ranges_of_different_types.ll
+++ llvm/test/Transforms/IRCE/ranges_of_different_types.ll
@@ -84,9 +84,7 @@
 ; CHECK-NEXT:      [[SMAX1:%[^ ]+]] = select i1 [[CMP1]], i32 [[LEN_MINUS_SMAX]], i32 -13
 ; CHECK-NEXT:      [[SUB1:%[^ ]+]] = sub i32 %len, [[SMAX1]]
 ; CHECK-NEXT:      [[CMP2:%[^ ]+]] = icmp slt i32 [[SUB1]], 101
-; CHECK-NEXT:      [[SMAX2:%[^ ]+]] = select i1 [[CMP2]], i32 [[SUB1]], i32 101
-; CHECK-NEXT:      [[CMP3:%[^ ]+]] = icmp sgt i32 [[SMAX2]], 0
-; CHECK-NEXT:      %exit.mainloop.at = select i1 [[CMP3]], i32 [[SMAX2]], i32 0
+; CHECK-NEXT:      %exit.mainloop.at = select i1 [[CMP2]], i32 [[SUB1]], i32 101
 ; CHECK-NEXT:      br i1 true, label %loop.preloop.preheader
 ; CHECK:         loop.preloop:
 ; CHECK-NEXT:      %idx.preloop = phi i32 [ %idx.next.preloop, %in.bounds.preloop ], [ 0, %loop.preloop.preheader ]
@@ -291,9 +289,7 @@
 ; CHECK-NEXT:      [[SMAX1:%[^ ]+]] = select i1 [[CMP1]], i32 [[LEN_MINUS_SMAX]], i32 -13
 ; CHECK-NEXT:      [[SUB1:%[^ ]+]] = sub i32 %len, [[SMAX1]]
 ; CHECK-NEXT:      [[CMP2:%[^ ]+]] = icmp slt i32 [[SUB1]], 101
-; CHECK-NEXT:      [[SMAX2:%[^ ]+]] = select i1 [[CMP2]], i32 [[SUB1]], i32 101
-; CHECK-NEXT:      [[CMP3:%[^ ]+]] = icmp sgt i32 [[SMAX2]], 0
-; CHECK-NEXT:      %exit.mainloop.at = select i1 [[CMP3]], i32 [[SMAX2]], i32 0
+; CHECK-NEXT:      %exit.mainloop.at = select i1 [[CMP2]], i32 [[SUB1]], i32 101
 ; CHECK-NEXT:      br i1 true, label %loop.preloop.preheader
 ; CHECK:         in.bounds.preloop:
 ; CHECK-NEXT:      %addr.preloop = getelementptr i32, i32* %arr, i32 %idx.preloop
Index: llvm/test/Analysis/ScalarEvolution/range_nw_flag.ll
===================================================================
--- llvm/test/Analysis/ScalarEvolution/range_nw_flag.ll
+++ llvm/test/Analysis/ScalarEvolution/range_nw_flag.ll
@@ -2,7 +2,7 @@
 
 ; copied from flags-from-poison.ll
 ; CHECK-LABEL: @test-add-nuw
-; CHECK: -->  {(1 + %offset)<nuw>,+,1}<nuw><%loop> U: full-set S: full-set
+; CHECK: -->  {(1 + %offset)<nuw>,+,1}<nuw><%loop> U: [1,0) S: [1,0)
 define void @test-add-nuw(float* %input, i32 %offset, i32 %numIterations) {
 entry:
   br label %loop
Index: llvm/lib/Analysis/ScalarEvolution.cpp
===================================================================
--- llvm/lib/Analysis/ScalarEvolution.cpp
+++ llvm/lib/Analysis/ScalarEvolution.cpp
@@ -5560,6 +5560,7 @@
 
   unsigned BitWidth = getTypeSizeInBits(S->getType());
   ConstantRange ConservativeResult(BitWidth, /*isFullSet=*/true);
+  using OBO = OverflowingBinaryOperator;
 
   // If the value has known zeros, the maximum value will have those known zeros
   // as well.
@@ -5577,8 +5578,14 @@
 
   if (const SCEVAddExpr *Add = dyn_cast<SCEVAddExpr>(S)) {
     ConstantRange X = getRangeRef(Add->getOperand(0), SignHint);
+    unsigned WrapType = OBO::AnyWrap;
+    if (Add->hasNoSignedWrap())
+      WrapType |= OBO::NoSignedWrap;
+    if (Add->hasNoUnsignedWrap())
+      WrapType |= OBO::NoUnsignedWrap;
     for (unsigned i = 1, e = Add->getNumOperands(); i != e; ++i)
-      X = X.add(getRangeRef(Add->getOperand(i), SignHint));
+      X = X.addWithNoWrap(getRangeRef(Add->getOperand(i), SignHint),
+                          WrapType);
     return setRange(Add, SignHint,
                     ConservativeResult.intersectWith(X, RangeType));
   }
Index: llvm/include/llvm/IR/Operator.h
===================================================================
--- llvm/include/llvm/IR/Operator.h
+++ llvm/include/llvm/IR/Operator.h
@@ -66,6 +66,7 @@
 class OverflowingBinaryOperator : public Operator {
 public:
   enum {
+    AnyWrap        = 0,
     NoUnsignedWrap = (1 << 0),
     NoSignedWrap   = (1 << 1)
   };


-------------- next part --------------
A non-text attachment was scrubbed...
Name: D64869.234678.patch
Type: text/x-patch
Size: 3833 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20191219/646df59b/attachment-0001.bin>