[mips] Account for endianess when expanding BuildPairF64/ExtractElementF64 nodes.

[vkalintiris]

Summary

In order to support big endian targets for the BuildPairF64 nodes we
just need to swap the low/high pair registers. Additionally, for the
ExtractElementF64 nodes we have to calculate the correct stack offset
with respect to the node's register/operand that we want to extract.

[vkalintiris]

Please, note that with these changes, the prefixes 32R2-FP64A-BE & 32R2-FP64A-LE in the file test/CodeGen/Mips/fp64a.ll
expect the same output. If the changes are fine, I will merge them under a new single check prefix in another review request.

[dsanders]

LGTM with 32R2-FP64A-LE and 32R2-FP64A-BE merged together.

test/CodeGen/Mips/fp64a.ll

40–44

Please merge 32R2-FP64A-LE and 32R2-FP64A-BE together now that they are the same.

[vkalintiris]

Merged the 32R2-FP64A-LE and 32R2-FP64A-BE check prefixes under a new common
prefix called 32R2-FP64A.

[vkalintiris]

Send correct update that includes the original review's changes.

Merged the 32R2-FP64A-LE and 32R2-FP64A-BE check prefixes under a new common
prefix called 32R2-FP64A.

[vkalintiris]

Closed by commit rL219931 (authored by @vkalintiris).

test/CodeGen/Mips/fp64a.ll

 ; Test that the FP64A ABI performs double precision moves via a spill/reload.
 ; The requirement is really that odd-numbered double precision registers do not
 ; use mfc1/mtc1 to move the bottom 32-bits (because the hardware will redirect
 ; this to the top 32-bits of the even register) but we have to make the decision
 ; before register allocation so we do this for all double-precision values.
 
 ; We don't test MIPS32r1 since support for 64-bit coprocessors (such as a 64-bit
 ; FPU) on a 32-bit architecture was added in MIPS32r2.
 ; FIXME: We currently don't test that attempting to use FP64 on MIPS32r1 is an
 ;        error either. This is because a large number of CodeGen tests are
 ;        incorrectly using this case. We should fix those test cases then add
 ;        this check here.
 
 ; RUN: llc -march=mips -mcpu=mips32r2 -mattr=fp64 < %s | FileCheck %s -check-prefix=ALL -check-prefix=32R2-NO-FP64A-BE
-; RUN: llc -march=mips -mcpu=mips32r2 -mattr=fp64,nooddspreg < %s | FileCheck %s -check-prefix=ALL -check-prefix=32R2-FP64A-BE
+; RUN: llc -march=mips -mcpu=mips32r2 -mattr=fp64,nooddspreg < %s | FileCheck %s -check-prefix=ALL -check-prefix=32R2-FP64A
 ; RUN: llc -march=mipsel -mcpu=mips32r2 -mattr=fp64 < %s | FileCheck %s -check-prefix=ALL -check-prefix=32R2-NO-FP64A-LE
-; RUN: llc -march=mipsel -mcpu=mips32r2 -mattr=fp64,nooddspreg < %s | FileCheck %s -check-prefix=ALL -check-prefix=32R2-FP64A-LE
+; RUN: llc -march=mipsel -mcpu=mips32r2 -mattr=fp64,nooddspreg < %s | FileCheck %s -check-prefix=ALL -check-prefix=32R2-FP64A
 
 ; RUN: llc -march=mips64 -mcpu=mips64 -mattr=fp64 < %s | FileCheck %s -check-prefix=ALL -check-prefix=64-NO-FP64A
 ; RUN: not llc -march=mips64 -mcpu=mips64 -mattr=fp64,nooddspreg < %s 2>&1 | FileCheck %s -check-prefix=64-FP64A
 ; RUN: llc -march=mips64el -mcpu=mips64 -mattr=fp64 < %s | FileCheck %s -check-prefix=ALL -check-prefix=64-NO-FP64A
 ; RUN: not llc -march=mips64el -mcpu=mips64 -mattr=fp64,nooddspreg < %s 2>&1 | FileCheck %s -check-prefix=64-FP64A
 
 ; 64-FP64A: LLVM ERROR: -mattr=+nooddspreg requires the O32 ABI.
 
 declare double @dbl();
 
 define double @call1(double %d, ...) {
   ret double %d
 
 ; ALL-LABEL:            call1:
 
 ; 32R2-NO-FP64A-LE-NOT:     addiu   $sp, $sp
 ; 32R2-NO-FP64A-LE:         mtc1    $4, $f0
 ; 32R2-NO-FP64A-LE:         mthc1   $5, $f0
 
 ; 32R2-NO-FP64A-BE-NOT:     addiu   $sp, $sp
 ; 32R2-NO-FP64A-BE:         mtc1    $5, $f0
 ; 32R2-NO-FP64A-BE:         mthc1   $4, $f0
 
-; 32R2-FP64A-LE:            addiu   $sp, $sp, -8
-; 32R2-FP64A-LE:            sw      $4, 0($sp)
-; 32R2-FP64A-LE:            sw      $5, 4($sp)
-; 32R2-FP64A-LE:            ldc1    $f0, 0($sp)
-
-; 32R2-FP64A-BE:            addiu   $sp, $sp, -8
-; 32R2-FP64A-BE:            sw      $4, 0($sp)
-; 32R2-FP64A-BE:            sw      $5, 4($sp)
-; 32R2-FP64A-BE:            ldc1    $f0, 0($sp)
+; 32R2-FP64A:               addiu   $sp, $sp, -8
+; 32R2-FP64A:               sw      $4, 0($sp)
+; 32R2-FP64A:               sw      $5, 4($sp)
+; 32R2-FP64A:               ldc1    $f0, 0($sp)
 
 ; 64-NO-FP64A:              daddiu  $sp, $sp, -64
 ; 64-NO-FP64A:              mov.d   $f0, $f12
 }
 
 define double @call2(i32 %i, double %d) {
   ret double %d
 
 ; ALL-LABEL:        call2:
 
 ; 32R2-NO-FP64A-LE:     mtc1    $6, $f0
 ; 32R2-NO-FP64A-LE:     mthc1   $7, $f0
 
 ; 32R2-NO-FP64A-BE:     mtc1    $7, $f0
 ; 32R2-NO-FP64A-BE:     mthc1   $6, $f0
 
-; 32R2-FP64A-LE:        addiu   $sp, $sp, -8
-; 32R2-FP64A-LE:        sw      $6, 0($sp)
-; 32R2-FP64A-LE:        sw      $7, 4($sp)
-; 32R2-FP64A-LE:        ldc1    $f0, 0($sp)
-
-; 32R2-FP64A-BE:        addiu   $sp, $sp, -8
-; 32R2-FP64A-BE:        sw      $6, 0($sp)
-; 32R2-FP64A-BE:        sw      $7, 4($sp)
-; 32R2-FP64A-BE:        ldc1    $f0, 0($sp)
+; 32R2-FP64A:           addiu   $sp, $sp, -8
+; 32R2-FP64A:           sw      $6, 0($sp)
+; 32R2-FP64A:           sw      $7, 4($sp)
+; 32R2-FP64A:           ldc1    $f0, 0($sp)
 
 ; 64-NO-FP64A-NOT:      daddiu  $sp, $sp
 ; 64-NO-FP64A:          mov.d   $f0, $f13
 }
 
 define double @call3(float %f1, float %f2, double %d) {
   ret double %d
 
 ; ALL-LABEL:        call3:
 
 ; 32R2-NO-FP64A-LE:     mtc1    $6, $f0
 ; 32R2-NO-FP64A-LE:     mthc1   $7, $f0
 
 ; 32R2-NO-FP64A-BE:     mtc1    $7, $f0
 ; 32R2-NO-FP64A-BE:     mthc1   $6, $f0
 
-; 32R2-FP64A-LE:        addiu   $sp, $sp, -8
-; 32R2-FP64A-LE:        sw      $6, 0($sp)
-; 32R2-FP64A-LE:        sw      $7, 4($sp)
-; 32R2-FP64A-LE:        ldc1    $f0, 0($sp)
-
-; 32R2-FP64A-BE:        addiu   $sp, $sp, -8
-; 32R2-FP64A-BE:        sw      $6, 0($sp)
-; 32R2-FP64A-BE:        sw      $7, 4($sp)
-; 32R2-FP64A-BE:        ldc1    $f0, 0($sp)
+; 32R2-FP64A:           addiu   $sp, $sp, -8
+; 32R2-FP64A:           sw      $6, 0($sp)
+; 32R2-FP64A:           sw      $7, 4($sp)
+; 32R2-FP64A:           ldc1    $f0, 0($sp)
 
 ; 64-NO-FP64A-NOT:      daddiu  $sp, $sp
 ; 64-NO-FP64A:          mov.d   $f0, $f14
 }
 
 define double @call4(float %f, double %d, ...) {
   ret double %d
 
 ; ALL-LABEL:        call4:
 
 ; 32R2-NO-FP64A-LE:     mtc1    $6, $f0
 ; 32R2-NO-FP64A-LE:     mthc1   $7, $f0
 
 ; 32R2-NO-FP64A-BE:     mtc1    $7, $f0
 ; 32R2-NO-FP64A-BE:     mthc1   $6, $f0
 
-; 32R2-FP64A-LE:        addiu   $sp, $sp, -8
-; 32R2-FP64A-LE:        sw      $6, 0($sp)
-; 32R2-FP64A-LE:        sw      $7, 4($sp)
-; 32R2-FP64A-LE:        ldc1    $f0, 0($sp)
-
-; 32R2-FP64A-BE:        addiu   $sp, $sp, -8
-; 32R2-FP64A-BE:        sw      $6, 0($sp)
-; 32R2-FP64A-BE:        sw      $7, 4($sp)
-; 32R2-FP64A-BE:        ldc1    $f0, 0($sp)
+; 32R2-FP64A:           addiu   $sp, $sp, -8
+; 32R2-FP64A:           sw      $6, 0($sp)
+; 32R2-FP64A:           sw      $7, 4($sp)
+; 32R2-FP64A:           ldc1    $f0, 0($sp)
 
 ; 64-NO-FP64A:          daddiu  $sp, $sp, -48
 ; 64-NO-FP64A:          mov.d   $f0, $f13
 }
 
 define double @call5(double %a, double %b, ...) {
   %1 = fsub double %a, %b
   ret double %1
 
 ; ALL-LABEL:            call5:
 
 ; 32R2-NO-FP64A-LE-DAG:     mtc1    $4, $[[T0:f[0-9]+]]
 ; 32R2-NO-FP64A-LE-DAG:     mthc1   $5, $[[T0:f[0-9]+]]
 ; 32R2-NO-FP64A-LE-DAG:     mtc1    $6, $[[T1:f[0-9]+]]
 ; 32R2-NO-FP64A-LE-DAG:     mthc1   $7, $[[T1:f[0-9]+]]
 ; 32R2-NO-FP64A-LE:         sub.d   $f0, $[[T0]], $[[T1]]
 
 ; 32R2-NO-FP64A-BE-DAG:     mtc1    $5, $[[T0:f[0-9]+]]
 ; 32R2-NO-FP64A-BE-DAG:     mthc1   $4, $[[T0:f[0-9]+]]
 ; 32R2-NO-FP64A-BE-DAG:     mtc1    $7, $[[T1:f[0-9]+]]
 ; 32R2-NO-FP64A-BE-DAG:     mthc1   $6, $[[T1:f[0-9]+]]
 ; 32R2-NO-FP64A-BE:         sub.d   $f0, $[[T0]], $[[T1]]
 
-; 32R2-FP64A-LE:            addiu   $sp, $sp, -8
-; 32R2-FP64A-LE:            sw      $6, 0($sp)
-; 32R2-FP64A-LE:            sw      $7, 4($sp)
-; 32R2-FP64A-LE:            ldc1    $[[T1:f[0-9]+]], 0($sp)
-; 32R2-FP64A-LE:            sw      $4, 0($sp)
-; 32R2-FP64A-LE:            sw      $5, 4($sp)
-; 32R2-FP64A-LE:            ldc1    $[[T0:f[0-9]+]], 0($sp)
-; 32R2-FP64A-LE:            sub.d   $f0, $[[T0]], $[[T1]]
-
-; 32R2-FP64A-BE:            addiu   $sp, $sp, -8
-; 32R2-FP64A-BE:            sw      $6, 0($sp)
-; 32R2-FP64A-BE:            sw      $7, 4($sp)
-; 32R2-FP64A-BE:            ldc1    $[[T1:f[0-9]+]], 0($sp)
-; 32R2-FP64A-BE:            sw      $4, 0($sp)
-; 32R2-FP64A-BE:            sw      $5, 4($sp)
-; 32R2-FP64A-BE:            ldc1    $[[T0:f[0-9]+]], 0($sp)
-; 32R2-FP64A-BE:            sub.d   $f0, $[[T0]], $[[T1]]
+; 32R2-FP64A:               addiu   $sp, $sp, -8
+; 32R2-FP64A:               sw      $6, 0($sp)
+; 32R2-FP64A:               sw      $7, 4($sp)
+; 32R2-FP64A:               ldc1    $[[T1:f[0-9]+]], 0($sp)
+; 32R2-FP64A:               sw      $4, 0($sp)
+; 32R2-FP64A:               sw      $5, 4($sp)
+; 32R2-FP64A:               ldc1    $[[T0:f[0-9]+]], 0($sp)
+; 32R2-FP64A:               sub.d   $f0, $[[T0]], $[[T1]]
 
 ; 64-NO-FP64A:              sub.d   $f0, $f12, $f13
 }
 
 define double @move_from(double %d) {
   %1 = call double @dbl()
   %2 = call double @call2(i32 0, double %1)
   ret double %2
 
 ; ALL-LABEL:        move_from:
 
 ; 32R2-NO-FP64A-LE-DAG: mfc1    $6, $f0
 ; 32R2-NO-FP64A-LE-DAG: mfhc1   $7, $f0
 
 ; 32R2-NO-FP64A-BE-DAG: mfc1    $7, $f0
 ; 32R2-NO-FP64A-BE-DAG: mfhc1   $6, $f0
 
-; 32R2-FP64A-LE:        addiu   $sp, $sp, -32
-; 32R2-FP64A-LE:        sdc1    $f0, 16($sp)
-; 32R2-FP64A-LE:        lw      $6, 16($sp)
+; 32R2-FP64A:           addiu   $sp, $sp, -32
+; 32R2-FP64A:           sdc1    $f0, 16($sp)
+; 32R2-FP64A:           lw      $6, 16($sp)
 ; FIXME: This store is redundant
-; 32R2-FP64A-LE:        sdc1    $f0, 16($sp)
-; 32R2-FP64A-LE:        lw      $7, 20($sp)
-
-; 32R2-FP64A-BE:        addiu   $sp, $sp, -32
-; 32R2-FP64A-BE:        sdc1    $f0, 16($sp)
-; 32R2-FP64A-BE:        lw      $6, 16($sp)
-; FIXME: This store is redundant
-; 32R2-FP64A-BE:        sdc1    $f0, 16($sp)
-; 32R2-FP64A-BE:        lw      $7, 20($sp)
+; 32R2-FP64A:           sdc1    $f0, 16($sp)
+; 32R2-FP64A:           lw      $7, 20($sp)
 
 ; 64-NO-FP64A:          mov.d   $f13, $f0
 }