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[PowerPC 2/4] Little-endian adjustments for VSX insert/extract operations 

For little endian, we need to make some straightforward adjustments in
the code expansions for scalar_to_vector and vector_extract of v2f64.
First, scalar_to_vector must place the scalar into vector element
zero.  However, our implementation of SUBREG_TO_REG will place it into
big-element vector element zero (high-order bits), and for little
endian we need it in the low-order bits.  The LE implementation splats
the high-order doubleword into the low-order doubleword.

Second, the meaning of (vector_extract x, 0) and (vector_extract x, 1)
must be reversed for similar reasons.

A new test is added that tests code generation for insertelement and
extractelement for both element 0 and element 1.  It is disabled in
this patch but enabled in patch 4/4, for reasons stated in the test.

llvm-svn: 223788
This commit is contained in:
Bill Schmidt 2014-12-09 16:43:32 +00:00
parent cbc5703aeb
commit 10f6eb91a0
1 changed files with 14 additions and 0 deletions
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14
llvm/lib/Target/PowerPC/PPCInstrVSX.td
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@ -793,6 +793,8 @@ def : InstAlias<"xxswapd $XT, $XB",
(XXPERMDI vsrc:$XT, vsrc:$XB, vsrc:$XB, 2)>;
let AddedComplexity = 400 in { // Prefer VSX patterns over non-VSX patterns.
let Predicates = [IsBigEndian] in {
def : Pat<(v2f64 (scalar_to_vector f64:$A)),
(v2f64 (SUBREG_TO_REG (i64 1), $A, sub_64))>;
@ -800,6 +802,18 @@ def : Pat<(f64 (vector_extract v2f64:$S, 0)),
(f64 (EXTRACT_SUBREG $S, sub_64))>;
def : Pat<(f64 (vector_extract v2f64:$S, 1)),
(f64 (EXTRACT_SUBREG (XXPERMDI $S, $S, 2), sub_64))>;
}
let Predicates = [IsLittleEndian] in {
def : Pat<(v2f64 (scalar_to_vector f64:$A)),
(v2f64 (XXPERMDI (SUBREG_TO_REG (i64 1), $A, sub_64),
(SUBREG_TO_REG (i64 1), $A, sub_64), 0))>;
def : Pat<(f64 (vector_extract v2f64:$S, 0)),
(f64 (EXTRACT_SUBREG (XXPERMDI $S, $S, 2), sub_64))>;
def : Pat<(f64 (vector_extract v2f64:$S, 1)),
(f64 (EXTRACT_SUBREG $S, sub_64))>;
}
// Additional fnmsub patterns: -a*c + b == -(a*c - b)
def : Pat<(fma (fneg f64:$A), f64:$C, f64:$B),