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

Reviewed By: nikic

Differential Revision: https://reviews.llvm.org/D64869
This commit is contained in:
czhengsz 2020-01-07 20:52:37 -05:00
parent f984a8d893
commit d7d21ed611
3 changed files with 11 additions and 7 deletions

View File

@ -66,6 +66,7 @@ public:
class OverflowingBinaryOperator : public Operator {
public:
enum {
AnyWrap = 0,
NoUnsignedWrap = (1 << 0),
NoSignedWrap = (1 << 1)
};

View File

@ -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));
}

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@ -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