[mips] [IAS] Reformat mips-expansions.s. NFC.

[tomatabacu]

Summary

Make mips-expansions.s more readable by grouping the instructions with their respective CHECK's.
This test is going to get a lot bigger soon and it will become essentially unreadable if the current formatting is kept.

I've also made the comments more useful and accurate, and I've restricted the RUN lines to under 80 columns.

[dsanders]

LGTM

test/MC/Mips/mips-expansions.s

-# RUN: llvm-mc %s -triple=mipsel-unknown-linux -show-encoding -mcpu=mips32r2 | FileCheck %s
-# Check that the assembler can handle the documented syntax
-# for macro instructions
-#------------------------------------------------------------------------------
-# Load immediate instructions
-#------------------------------------------------------------------------------
+# RUN: llvm-mc %s -triple=mipsel-unknown-linux -show-encoding -mcpu=mips32r2 | \
+# RUN:   FileCheck %s
+
+# Check that the IAS expands macro instructions in the same way as GAS.
+
+# Load immediate, done by MipsAsmParser::expandLoadImm():
+  li $5, 123
 # CHECK:     ori     $5, $zero, 123   # encoding: [0x7b,0x00,0x05,0x34]
+  li $6, -2345
 # CHECK:     addiu   $6, $zero, -2345 # encoding: [0xd7,0xf6,0x06,0x24]
+  li $7, 65538
 # CHECK:     lui     $7, 1            # encoding: [0x01,0x00,0x07,0x3c]
 # CHECK:     ori     $7, $7, 2        # encoding: [0x02,0x00,0xe7,0x34]
+  li $8, ~7
 # CHECK:     addiu   $8, $zero, -8    # encoding: [0xf8,0xff,0x08,0x24]
+  li $9, 0x10000
 # CHECK:     lui     $9, 1            # encoding: [0x01,0x00,0x09,0x3c]
 # CHECK-NOT: ori $9, $9, 0            # encoding: [0x00,0x00,0x29,0x35]
+  li $10, ~(0x101010)
 # CHECK:     lui     $10, 65519       # encoding: [0xef,0xff,0x0a,0x3c]
 # CHECK:     ori     $10, $10, 61423  # encoding: [0xef,0xef,0x4a,0x35]
 
+# Load address, done by MipsAsmParser::expandLoadAddressReg()
+# and MipsAsmParser::expandLoadAddressImm():
+  la $4, 20
 # CHECK: ori     $4, $zero, 20       # encoding: [0x14,0x00,0x04,0x34]
+  la $7, 65538
 # CHECK: lui     $7, 1               # encoding: [0x01,0x00,0x07,0x3c]
 # CHECK: ori     $7, $7, 2           # encoding: [0x02,0x00,0xe7,0x34]
+  la $4, 20($5)
 # CHECK: ori     $4, $5, 20          # encoding: [0x14,0x00,0xa4,0x34]
+  la $7, 65538($8)
 # CHECK: lui     $7, 1               # encoding: [0x01,0x00,0x07,0x3c]
 # CHECK: ori     $7, $7, 2           # encoding: [0x02,0x00,0xe7,0x34]
 # CHECK: addu    $7, $7, $8          # encoding: [0x21,0x38,0xe8,0x00]
+  la $8, symbol
 # CHECK: lui     $8, %hi(symbol)     # encoding: [A,A,0x08,0x3c]
 # CHECK:                             #   fixup A - offset: 0, value: symbol@ABS_HI, kind: fixup_Mips_HI16
 # CHECK: ori     $8, $8, %lo(symbol) # encoding: [A,A,0x08,0x35]
 # CHECK:                             #   fixup A - offset: 0, value: symbol@ABS_LO, kind: fixup_Mips_LO16
+
+# LW/SW and LDC1/SDC1 of symbol address, done by MipsAsmParser::expandMemInst():
+  .set noat
+  lw $10, symbol($4)
 # CHECK: lui     $10, %hi(symbol)        # encoding: [A,A,0x0a,0x3c]
 # CHECK:                                 #   fixup A - offset: 0, value: symbol@ABS_HI, kind: fixup_Mips_HI16
 # CHECK: addu    $10, $10, $4            # encoding: [0x21,0x50,0x44,0x01]
 # CHECK: lw      $10, %lo(symbol)($10)   # encoding: [A,A,0x4a,0x8d]
 # CHECK:                                 #   fixup A - offset: 0, value: symbol@ABS_LO, kind: fixup_Mips_LO16
+  .set at
+  sw $10, symbol($9)
 # CHECK: lui     $1, %hi(symbol)         # encoding: [A,A,0x01,0x3c]
 # CHECK:                                 #   fixup A - offset: 0, value: symbol@ABS_HI, kind: fixup_Mips_HI16
 # CHECK: addu    $1, $1, $9              # encoding: [0x21,0x08,0x29,0x00]
 # CHECK: sw      $10, %lo(symbol)($1)    # encoding: [A,A,0x2a,0xac]
 # CHECK:                                 #   fixup A - offset: 0, value: symbol@ABS_LO, kind: fixup_Mips_LO16
+
+  lw $10, 655483($4)
 # CHECK: lui     $10, 10                 # encoding: [0x0a,0x00,0x0a,0x3c]
 # CHECK: addu    $10, $10, $4            # encoding: [0x21,0x50,0x44,0x01]
 # CHECK: lw      $10, 123($10)           # encoding: [0x7b,0x00,0x4a,0x8d]
+  sw $10, 123456($9)
 # CHECK: lui     $1, 2                   # encoding: [0x02,0x00,0x01,0x3c]
 # CHECK: addu    $1, $1, $9              # encoding: [0x21,0x08,0x29,0x00]
 # CHECK: sw      $10, 57920($1)          # encoding: [0x40,0xe2,0x2a,0xac]
 
+  lw $8, symbol
 # CHECK:     lui     $8, %hi(symbol)     # encoding: [A,A,0x08,0x3c]
 # CHECK:                                 #   fixup A - offset: 0, value: symbol@ABS_HI, kind: fixup_Mips_HI16
 # CHECK-NOT: move    $8, $8              # encoding: [0x21,0x40,0x00,0x01]
 # CHECK:     lw      $8, %lo(symbol)($8) # encoding: [A,A,0x08,0x8d]
 # CHECK:                                 #   fixup A - offset: 0, value: symbol@ABS_LO, kind: fixup_Mips_LO16
+  sw $8, symbol
 # CHECK:     lui     $1, %hi(symbol)     # encoding: [A,A,0x01,0x3c]
 # CHECK:                                 #   fixup A - offset: 0, value: symbol@ABS_HI, kind: fixup_Mips_HI16
 # CHECK-NOT: move    $1, $1              # encoding: [0x21,0x08,0x20,0x00]
 # CHECK:     sw      $8, %lo(symbol)($1) # encoding: [A,A,0x28,0xac]
 # CHECK:                                 #   fixup A - offset: 0, value: symbol@ABS_LO, kind: fixup_Mips_LO16
 
+  ldc1 $f0, symbol
 # CHECK: lui     $1, %hi(symbol)
 # CHECK: ldc1    $f0, %lo(symbol)($1)
+  sdc1 $f0, symbol
 # CHECK: lui     $1, %hi(symbol)
 # CHECK: sdc1    $f0, %lo(symbol)($1)
-
-    li $5,123
-    li $6,-2345
-    li $7,65538
-    li $8, ~7
-    li $9, 0x10000
-    li $10, ~(0x101010)
-
-    la $a0, 20
-    la $7,65538
-    la $a0, 20($a1)
-    la $7,65538($8)
-    la $t0, symbol
-
-    .set noat
-    lw  $t2, symbol($a0)
-    .set at
-    sw  $t2, symbol($t1)
-
-    lw  $t2, 655483($a0)
-    sw  $t2, 123456($t1)
-
-    lw  $8, symbol
-    sw  $8, symbol
-
-    ldc1 $f0, symbol
-    sdc1 $f0, symbol