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| author | Sanjay Patel <spatel@rotateright.com> | 2018-03-14 21:23:27 +0000 |
|---|---|---|
| committer | Sanjay Patel <spatel@rotateright.com> | 2018-03-14 21:23:27 +0000 |
| commit | 11f7f9908b139f480c9571c723ddffa3e8e7a08c (patch) | |
| tree | 336c899a4b308b4a37c72fa09f4b2266b82640ea /llvm/lib/CodeGen/MachineOperand.cpp | |
| parent | a5c1ed340f1abaed46397e547d86986e570c3382 (diff) | |
| download | bcm5719-llvm-11f7f9908b139f480c9571c723ddffa3e8e7a08c.tar.gz bcm5719-llvm-11f7f9908b139f480c9571c723ddffa3e8e7a08c.zip | |
[InstSimplify] fix folds for (0.0 - X) + X --> 0 (PR27151)
As shown in:
https://bugs.llvm.org/show_bug.cgi?id=27151
...the existing fold could miscompile when X is NaN.
The fold was also dependent on 'ninf' but that's not necessary.
From IEEE-754 (with default rounding which we can assume for these opcodes):
"When the sum of two operands with opposite signs (or the difference of two
operands with like signs) is exactly zero, the sign of that sum (or difference)
shall be +0...However, x + x = x − (−x) retains the same sign as x even when
x is zero."
llvm-svn: 327575
Diffstat (limited to 'llvm/lib/CodeGen/MachineOperand.cpp')
0 files changed, 0 insertions, 0 deletions
