diff options
Diffstat (limited to 'src/jit/decomposelongs.cpp')
| -rw-r--r-- | src/jit/decomposelongs.cpp | 119 |
1 files changed, 30 insertions, 89 deletions
diff --git a/src/jit/decomposelongs.cpp b/src/jit/decomposelongs.cpp index 89092b08b9..7caae4743c 100644 --- a/src/jit/decomposelongs.cpp +++ b/src/jit/decomposelongs.cpp @@ -1087,7 +1087,9 @@ GenTree* DecomposeLongs::DecomposeShift(LIR::Use& use) // If we are shifting by a constant int, we do not want to use a helper, instead, we decompose. if (shiftByOper == GT_CNS_INT) { - unsigned int count = shiftByOp->gtIntCon.gtIconVal; + // Reduce count modulo 64 to match behavior found in the shift helpers, + // Compiler::gtFoldExpr and ValueNumStore::EvalOpIntegral. + unsigned int count = shiftByOp->gtIntCon.gtIconVal & 0x3F; Range().Remove(shiftByOp); if (count == 0) @@ -1112,24 +1114,6 @@ GenTree* DecomposeLongs::DecomposeShift(LIR::Use& use) { case GT_LSH: { - // Reduce count modulo 64 to match behavior found in - // the LLSH helper and in gtFoldExpr. - count &= 0x3F; - - // Retest for zero shift - if (count == 0) - { - GenTree* next = shift->gtNext; - // Remove shift and don't do anything else. - if (shift->IsUnusedValue()) - { - gtLong->SetUnusedValue(); - } - Range().Remove(shift); - use.ReplaceWith(m_compiler, gtLong); - return next; - } - if (count < 32) { // For shifts of < 32 bits, we transform the code to: @@ -1258,6 +1242,8 @@ GenTree* DecomposeLongs::DecomposeShift(LIR::Use& use) } else { + assert(count >= 32 && count < 64); + // Since we're right shifting at least 32 bits, we can remove the lo part of the shifted value iff // it has no side effects. // @@ -1272,45 +1258,19 @@ GenTree* DecomposeLongs::DecomposeShift(LIR::Use& use) loOp1->SetUnusedValue(); } - assert(count >= 32); - if (count < 64) + if (count == 32) { - if (count == 32) - { - // Move hiOp1 into loResult. - loResult = hiOp1; - } - else - { - assert(count > 32 && count < 64); - - // Move hiOp1 into loResult, do a GT_RSZ with count - 32. - GenTree* shiftBy = m_compiler->gtNewIconNode(count - 32, TYP_INT); - loResult = m_compiler->gtNewOperNode(oper, TYP_INT, hiOp1, shiftBy); - Range().InsertBefore(shift, shiftBy, loResult); - } + // Move hiOp1 into loResult. + loResult = hiOp1; } else { - assert(count >= 64); - - // Since we're right shifting at least 64 bits, we can remove the hi part of the shifted value - // iff it has no side effects. - // - // TODO-CQ: we could go perform this removal transitively (i.e. iteratively remove everything - // that feeds the hi operand while there are no side effects) - if ((hiOp1->gtFlags & GTF_ALL_EFFECT) == 0) - { - Range().Remove(hiOp1, true); - } - else - { - hiOp1->SetUnusedValue(); - } - - // Zero out lo - loResult = m_compiler->gtNewZeroConNode(TYP_INT); - Range().InsertBefore(shift, loResult); + assert(count > 32 && count < 64); + + // Move hiOp1 into loResult, do a GT_RSZ with count - 32. + GenTree* shiftBy = m_compiler->gtNewIconNode(count - 32, TYP_INT); + loResult = m_compiler->gtNewOperNode(oper, TYP_INT, hiOp1, shiftBy); + Range().InsertBefore(shift, shiftBy, loResult); } // Zero out hi @@ -1354,7 +1314,7 @@ GenTree* DecomposeLongs::DecomposeShift(LIR::Use& use) } else { - assert(count >= 32); + assert(count >= 32 && count < 64); // Since we're right shifting at least 32 bits, we can remove the lo part of the shifted value iff // it has no side effects. @@ -1370,47 +1330,28 @@ GenTree* DecomposeLongs::DecomposeShift(LIR::Use& use) loOp1->SetUnusedValue(); } - if (count < 64) + if (count == 32) { - if (count == 32) - { - // Move hiOp1 into loResult. - loResult = hiOp1; - Range().InsertBefore(shift, loResult); - } - else - { - assert(count > 32 && count < 64); - - // Move hiOp1 into loResult, do a GT_RSH with count - 32. - GenTree* shiftBy = m_compiler->gtNewIconNode(count - 32, TYP_INT); - loResult = m_compiler->gtNewOperNode(oper, TYP_INT, hiOp1, shiftBy); - Range().InsertBefore(shift, hiOp1, shiftBy, loResult); - } - - // Propagate sign bit in hiResult - GenTree* shiftBy = m_compiler->gtNewIconNode(31, TYP_INT); - hiResult = m_compiler->gtNewOperNode(GT_RSH, TYP_INT, hiCopy, shiftBy); - Range().InsertBefore(shift, shiftBy, hiCopy, hiResult); - - m_compiler->lvaIncRefCnts(hiCopy); + // Move hiOp1 into loResult. + loResult = hiOp1; + Range().InsertBefore(shift, loResult); } else { - assert(count >= 64); + assert(count > 32 && count < 64); - // Propagate sign bit in loResult - GenTree* loShiftBy = m_compiler->gtNewIconNode(31, TYP_INT); - loResult = m_compiler->gtNewOperNode(GT_RSH, TYP_INT, hiCopy, loShiftBy); - Range().InsertBefore(shift, hiCopy, loShiftBy, loResult); + // Move hiOp1 into loResult, do a GT_RSH with count - 32. + GenTree* shiftBy = m_compiler->gtNewIconNode(count - 32, TYP_INT); + loResult = m_compiler->gtNewOperNode(oper, TYP_INT, hiOp1, shiftBy); + Range().InsertBefore(shift, hiOp1, shiftBy, loResult); + } - // Propagate sign bit in hiResult - GenTree* shiftBy = m_compiler->gtNewIconNode(31, TYP_INT); - hiResult = m_compiler->gtNewOperNode(GT_RSH, TYP_INT, hiOp1, shiftBy); - Range().InsertBefore(shift, shiftBy, hiOp1, hiResult); + // Propagate sign bit in hiResult + GenTree* shiftBy = m_compiler->gtNewIconNode(31, TYP_INT); + hiResult = m_compiler->gtNewOperNode(GT_RSH, TYP_INT, hiCopy, shiftBy); + Range().InsertBefore(shift, shiftBy, hiCopy, hiResult); - m_compiler->lvaIncRefCnts(hiCopy); - } + m_compiler->lvaIncRefCnts(hiCopy); } insertAfter = hiResult; |