Commit Graph

5 Commits

Author SHA1 Message Date
Quentin Colombet a7439d4483 [X86] Do not custom lower UINT_TO_FP when the target type does not
match the custom lowering.

<rdar://problem/19026326>

llvm-svn: 222489
2014-11-21 00:47:19 +00:00
Quentin Colombet 360460ba64 [X86] Custom lower UINT_TO_FP from v4f32 to v4i32, and for v8f32 to v8i32 if
AVX2 is available.
According to IACA, the new lowering has a throughput of 8 cycles instead of 13
with the previous one.

Althought this lowering kicks in some SPECs benchmarks, the performance
improvement was within the noise.

Correctness testing has been done for the whole range of uint32_t with the
following program:
    uint4 v = (uint4) {0,1,2,3};
    uint32_t i;
    
    //Check correctness over entire range for uint4 -> float4 conversion
    for( i = 0; i < 1U << (32-2); i++ )
    {
        float4 t = test(v);
        float4 c = correct(v);
        
        if( 0xf != _mm_movemask_ps( t == c ))
        {
            printf( "Error @ %vx: %vf vs. %vf\n", v, c, t);
            return -1;
        }
        
        v += 4;
    }
Where "correct" is the old lowering and "test" the new one.

The patch adds a test case for the two custom lowering instruction.
It also modifies the vector cost model, which is why cast.ll and uitofp.ll are
modified.
2009-02-26-MachineLICMBug.ll is also modified because we now hoist 7
instructions instead of 4 (3 more constant loads).

rdar://problem/18153096>

llvm-svn: 221657
2014-11-11 02:23:47 +00:00
Stephen Lin f799e3f944 Convert CodeGen/*/*.ll tests to use the new CHECK-LABEL for easier debugging. No functionality change and all tests pass after conversion.
This was done with the following sed invocation to catch label lines demarking function boundaries:
    sed -i '' "s/^;\( *\)\([A-Z0-9_]*\):\( *\)test\([A-Za-z0-9_-]*\):\( *\)$/;\1\2-LABEL:\3test\4:\5/g" test/CodeGen/*/*.ll
which was written conservatively to avoid false positives rather than false negatives. I scanned through all the changes and everything looks correct.

llvm-svn: 186258
2013-07-13 20:38:47 +00:00
Benjamin Kramer 0bf26746d9 Rename the "sandybridge" subtarget to "corei7-avx", for GCC compatibility.
llvm-svn: 131730
2011-05-20 15:11:26 +00:00
Nadav Rotem e7a101ccab Add support for legalizing UINT_TO_FP of vectors on platforms which do
not have native support for this operation (such as X86).
The legalized code uses two vector INT_TO_FP operations and is faster
than scalarizing.

llvm-svn: 127951
2011-03-19 13:09:10 +00:00