Add saturating addition/subtraction#6647
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tautschnig merged 2 commits intodiffblue:developfrom Feb 9, 2022
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@@ Coverage Diff @@
## develop #6647 +/- ##
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Coverage 76.73% 76.74%
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Files 1579 1579
Lines 182008 182173 +165
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+ Hits 139671 139803 +132
- Misses 42337 42370 +33
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peterschrammel
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chris-ryder
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chris-ryder
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Assuming I've followed all the bit operations correctly, I think that looks reasonable to me. As an aside, the phrase "For C code, it takes MMX instructions to have access to this" of course only applies to x86/amd64. ARM of course has it's own instructions and compiler intrinsics for saturated arithmetic.
| else if(expr.id() == ID_bitreverse) | ||
| return convert_bitreverse(to_bitreverse_expr(expr)); | ||
| else if(expr.id() == ID_saturating_minus || expr.id() == ID_saturating_plus) | ||
| return convert_saturating_add_sub(to_binary_expr(expr)); |
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Minor nit pick... there's a mis-match of terminology here - plus vs add, minus vs sub - should we pick one and settle?
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Rust natively supports saturating arithmetic. For C code, it takes MMX instructions to have access to this (which will be implemented in the next commit), and even then it is limited to addition and subtraction. The implementation now is equally restricted to these two arithmetic operations. Fixes: diffblue#5841
With the newly added saturating addition/subtraction it is possible to support MMX instructions performing saturating arithmetic over vectors.
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Rust natively supports saturating arithmetic. For C code, it takes MMX
instructions to have access to this, and even then it is limited to
addition and subtraction. The implementation now is equally restricted
to these two arithmetic operations.