[llvm] 8b8ba44 - [SCEV] get more accurate range for AddExpr with wrap flag.

[via llvm-commits]

Author: czhengsz
Date: 2020-01-07T20:58:04-05:00
New Revision: 8b8ba44047d44b846fcd197a7a553468f154649b

URL: https://github.com/llvm/llvm-project/commit/8b8ba44047d44b846fcd197a7a553468f154649b
DIFF: https://github.com/llvm/llvm-project/commit/8b8ba44047d44b846fcd197a7a553468f154649b.diff

LOG: [SCEV] get more accurate range for AddExpr with wrap flag.

Reviewed By: nikic

Differential Revision: https://reviews.llvm.org/D64869

Added: 
    

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

Removed: 
    


################################################################################
diff  --git a/llvm/include/llvm/IR/Operator.h b/llvm/include/llvm/IR/Operator.h
index c8ca7e9a00e8..35e08d9215e2 100644
--- a/llvm/include/llvm/IR/Operator.h
+++ b/llvm/include/llvm/IR/Operator.h
@@ -66,6 +66,7 @@ class Operator : public User {
 class OverflowingBinaryOperator : public Operator {
 public:
   enum {
+    AnyWrap        = 0,
     NoUnsignedWrap = (1 << 0),
     NoSignedWrap   = (1 << 1)
   };

diff  --git a/llvm/lib/Analysis/ScalarEvolution.cpp b/llvm/lib/Analysis/ScalarEvolution.cpp
index 5926bff5d23d..e636854ad6d9 100644
--- a/llvm/lib/Analysis/ScalarEvolution.cpp
+++ b/llvm/lib/Analysis/ScalarEvolution.cpp
@@ -5560,6 +5560,7 @@ ScalarEvolution::getRangeRef(const SCEV *S,
 
   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 @@ ScalarEvolution::getRangeRef(const SCEV *S,
 
   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, RangeType);
     return setRange(Add, SignHint,
                     ConservativeResult.intersectWith(X, RangeType));
   }

diff  --git a/llvm/test/Transforms/IRCE/ranges_of_
diff erent_types.ll b/llvm/test/Transforms/IRCE/ranges_of_
diff erent_types.ll
index d5c694b05ff7..9903cb147cf4 100644
--- a/llvm/test/Transforms/IRCE/ranges_of_
diff erent_types.ll
+++ b/llvm/test/Transforms/IRCE/ranges_of_
diff erent_types.ll
@@ -84,9 +84,7 @@ define void @test_02(i32* %arr, i32* %a_len_ptr) #0 {
 ; 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 @@ define void @test_06(i32* %arr, i32* %a_len_ptr) #0 {
 ; 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