Commit Graph

16 Commits

Author SHA1 Message Date
Richard Trieu 7561ed01cb Allow -1 to assign max value to unsigned bitfields.
Silence the -Wbitfield-constant-conversion warning for when -1 or other
negative values are assigned to unsigned bitfields, provided that the bitfield
is wider than the minimum number of bits needed to encode the negative value.

llvm-svn: 277796
2016-08-05 02:39:30 +00:00
Richard Trieu fc404c7fb3 Exempt char array initializers from -Wconstant-converion.
Sometimes, char arrays are used as bit storage, with no difference made between
signed and unsigned char.  Thus, it is reasonable to use 0 to 255 instead of
-128 to 127 and not trigger this warning.

llvm-svn: 259947
2016-02-05 23:02:38 +00:00
Richard Trieu dcb5557f2d Improve -Wconstant-conversion
Switch the evaluation from isIntegerConstantExpr to EvaluateAsInt.
EvaluateAsInt will evaluate more types of expressions than
isIntegerConstantExpr.

Move one case from -Wsign-conversion to -Wconstant-conversion.  The case is:
1) Source and target types are signed
2) Source type is wider than the target type
3) The source constant value is positive
4) The conversion will store the value as negative in the target.

llvm-svn: 259271
2016-01-29 23:51:16 +00:00
Timur Iskhodzhanov 554bdc66a4 Revert r178273 as it broke the Linux bootstrap due to false positives
llvm-svn: 178320
2013-03-29 00:22:03 +00:00
Sam Panzer 6fffec6fd4 Implemented a warning when an input several bitwise operations are
likely be implicitly truncated:

  * All forms of Bitwise-and, bitwise-or, and integer multiplication.
  * The assignment form of integer addition, subtraction, and exclusive-or
  * The RHS of the comma operator
  * The LHS of left shifts.

llvm-svn: 178273
2013-03-28 19:07:11 +00:00
Eli Friedman e1ffd49165 Change the check for constant-conversion with width-1 bitfields so it doesn't suppress quite as many cases. Based off a testcase in the gcc testsuite.
llvm-svn: 149572
2012-02-02 00:40:20 +00:00
Eli Friedman 66b6395dd5 Turn off implicit truncation warning for compound assignment to bitfields; it might be reasonable in some cases, but it clearly doesn't make sense in some cases, like the included testcase.
<rdar://problem/10238797>, part 2.

llvm-svn: 149095
2012-01-26 23:34:06 +00:00
Eli Friedman c267a32b05 Make the bitfield implicit truncation warning slightly more aggressive, and make the printed warning a bit more accurate. The new behavior matches gcc's -Wconversion. <rdar://problem/10238797>.
llvm-svn: 149089
2012-01-26 23:11:39 +00:00
Ted Kremenek 33ba99566f Only emit implicit constant conversion truncation warnings in reachable code. Apparently this is what GCC does, and some code depends on this. Fixes <rdar://problem/10321089>.
llvm-svn: 142716
2011-10-22 02:37:33 +00:00
John McCall deebbcf20d Undo a refactor-o and base the bitfield-truncation warning on the
uncoerced value.  Also, whitelist bool bitfields, which aren't
really a truncation.

llvm-svn: 118778
2010-11-11 05:33:51 +00:00
John McCall 1f425648ca Extend the bitfield-truncation warning to initializations.
rdar://problem/8652606

llvm-svn: 118773
2010-11-11 03:21:53 +00:00
John McCall 817d4af557 When -Wconversion computes the range of a type, it uses the (bit-)range
of the enumerators rather than the actual expressible range.  This is 
great when dealing with opaque *values* of that type, but when computing
the range of the type for purposes of converting *into* it, it produces
warnings in cases we don't care about (e.g. enum_t x = 500;).  Divide 
the logic into these two cases and use the more conservative range for
targets.    

llvm-svn: 118735
2010-11-10 23:38:19 +00:00
John McCall fd81c52947 Tweak to bitfield-overflow warning: don't warn about storing
a positive value into a signed bitfield of the exact width of
the value.

llvm-svn: 118657
2010-11-10 00:26:50 +00:00
John McCall 0e6cfaf6c0 Typo.
llvm-svn: 118649
2010-11-09 23:36:43 +00:00
John McCall d2a5312e14 Add a warning for implicit truncation of constant values due to
bitfield assignment.

Implements rdar://problem/7809123

llvm-svn: 118647
2010-11-09 23:24:47 +00:00
John McCall 18a2c2c0b9 Split out -Wconversion warnings about constant precision into their
own subcategory, -Wconstant-conversion, which is on by default.

Tweak the constant folder to give better results in the invalid
case of a negative shift amount.

Implements rdar://problem/6792488

llvm-svn: 118636
2010-11-09 22:22:12 +00:00