diff options
Diffstat (limited to 'llvm/lib/Transforms/InstCombine/InstCombineShifts.cpp')
| -rw-r--r-- | llvm/lib/Transforms/InstCombine/InstCombineShifts.cpp | 9 |
1 files changed, 5 insertions, 4 deletions
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineShifts.cpp b/llvm/lib/Transforms/InstCombine/InstCombineShifts.cpp index 48e9cfea9b3..2427d795c47 100644 --- a/llvm/lib/Transforms/InstCombine/InstCombineShifts.cpp +++ b/llvm/lib/Transforms/InstCombine/InstCombineShifts.cpp @@ -75,11 +75,12 @@ reassociateShiftAmtsOfTwoSameDirectionShifts(BinaryOperator *Sh0, // c) (x & (-1 >> MaskShAmt)) << ShiftShAmt // d) (x & ((-1 << MaskShAmt) >> MaskShAmt)) << ShiftShAmt // e) ((x << MaskShAmt) l>> MaskShAmt) << ShiftShAmt +// f) ((x << MaskShAmt) a>> MaskShAmt) << ShiftShAmt // All these patterns can be simplified to just: // x << ShiftShAmt // iff: -// a,b) (MaskShAmt+ShiftShAmt) u>= bitwidth(x) -// c,d,e) (ShiftShAmt-MaskShAmt) s>= 0 (i.e. ShiftShAmt u>= MaskShAmt) +// a,b) (MaskShAmt+ShiftShAmt) u>= bitwidth(x) +// c,d,e,f) (ShiftShAmt-MaskShAmt) s>= 0 (i.e. ShiftShAmt u>= MaskShAmt) static Instruction * dropRedundantMaskingOfLeftShiftInput(BinaryOperator *OuterShift, const SimplifyQuery &SQ) { @@ -117,8 +118,8 @@ dropRedundantMaskingOfLeftShiftInput(BinaryOperator *OuterShift, return nullptr; // All good, we can do this fold. } else if (match(Masked, m_c_And(m_CombineOr(MaskC, MaskD), m_Value(X))) || - match(Masked, m_LShr(m_Shl(m_Value(X), m_Value(MaskShAmt)), - m_Deferred(MaskShAmt)))) { + match(Masked, m_Shr(m_Shl(m_Value(X), m_Value(MaskShAmt)), + m_Deferred(MaskShAmt)))) { // Can we simplify (ShiftShAmt-MaskShAmt) ? Value *ShAmtsDiff = SimplifySubInst(ShiftShAmt, MaskShAmt, /*IsNSW=*/false, /*IsNUW=*/false, |
