[mips] Tolerate the use of the %z inline asm operand modifier with non-immediates.

Summary:
Currently, we give an error if %z is used with non-immediates, instead of continuing as if the %z isn't there.

For example, you use the %z operand modifier along with the "Jr" constraints ("r" makes the operand a register, and "J" makes it an immediate, but only if its value is 0). 
In this case, you want the compiler to print "$0" if the inline asm input operand turns out to be an immediate zero and you want it to print the register containing the operand, if it's not.

We give an error in the latter case, and we shouldn't (GCC also doesn't).

Reviewers: dsanders

Reviewed By: dsanders

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D6023

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221453 91177308-0d34-0410-b5e6-96231b3b80d8
Fixing some -Wcast-qual warnings; NFC.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221454 91177308-0d34-0410-b5e6-96231b3b80d8
[X86] When commuting SSE immediate blend, make sure that the new blend mask is a valid imm8.

Example:
define <4 x i32> @test(<4 x i32> %a, <4 x i32> %b) {
  %shuffle = shufflevector <4 x i32> %a, <4 x i32> %b, <4 x i32> <i32 4, i32 5, i32 6, i32 3>
  ret <4 x i32> %shuffle
}

Before llc (-mattr=+sse4.1), produced the following assembly instruction:
  pblendw $4294967103, %xmm1, %xmm0

After
  pblendw $63, %xmm1, %xmm0


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221455 91177308-0d34-0410-b5e6-96231b3b80d8
Compute the correct jump table entries on 32 bit windows.

On 32 bit windows we use label differences and .set does not suppress
rolocations, a combination that was not used before r220256.

This fixes PR21497.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221456 91177308-0d34-0410-b5e6-96231b3b80d8
Use FileCheck in a few tests.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221459 91177308-0d34-0410-b5e6-96231b3b80d8