[mips] Implement llvm.trap intrinsic.

Patch by Sasa Stankovic.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@187244 91177308-0d34-0410-b5e6-96231b3b80d8
Remove addLetterToHash, no functional change.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@187245 91177308-0d34-0410-b5e6-96231b3b80d8
Use more parens to clarify assert.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@187247 91177308-0d34-0410-b5e6-96231b3b80d8
[PowerPC] Improve consistency in use of __ppc__, __powerpc__, etc.

Both GCC and LLVM will implicitly define __ppc__ and __powerpc__ for
all PowerPC targets, whether 32- or 64-bit.  They will both implicitly
define __ppc64__ and __powerpc64__ for 64-bit PowerPC targets, and not
for 32-bit targets.  We cannot be sure that all other possible
compilers used to compile Clang/LLVM define both __ppc__ and
__powerpc__, for example, so it is best to check for both when relying
on either inside the Clang/LLVM code base.

This patch makes sure we always check for both variants.  In addition,
it fixes one unnecessary check in lib/Target/PowerPC/PPCJITInfo.cpp.
(At least one of __ppc__ and __powerpc__ should always be defined when
compiling for a PowerPC target, no matter which compiler is used, so
testing for them is unnecessary.)

There are some places in the compiler that check for other variants,
like __POWERPC__ and _POWER, and I have left those in place.  There is
no need to add them elsewhere.  This seems to be in Apple-specific
code, and I won't take a chance on breaking it.

There is no intended change in behavior; thus, no test cases are
added.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@187248 91177308-0d34-0410-b5e6-96231b3b80d8
When InstCombine tries to fold away (fsub x, (fneg y)) into (fadd x, y), it is
also worthwhile for it to look through FP extensions and truncations, whose
application commutes with fneg.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@187249 91177308-0d34-0410-b5e6-96231b3b80d8
Use a non-c'tor for converting a boolean into a StringRef.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@187250 91177308-0d34-0410-b5e6-96231b3b80d8