Improve the compression of the tablegen DiffLists by introducing a new sort

algorithm when assigning EnumValues to the synthesized registers.

The current algorithm, LessRecord, uses the StringRef compare_numeric
function.  This function compares strings, while handling embedded numbers.
For example, the R600 backend registers are sorted as follows:

  T1
  T1_W
  T1_X
  T1_XYZW
  T1_Y
  T1_Z
  T2
  T2_W
  T2_X
  T2_XYZW
  T2_Y
  T2_Z

In this example, the 'scaling factor' is dEnum/dN = 6 because T0, T1, T2
have an EnumValue offset of 6 from one another.  However, in other parts
of the register bank, the scaling factors are different:

dEnum/dN = 5:
  KC0_128_W
  KC0_128_X
  KC0_128_XYZW
  KC0_128_Y
  KC0_128_Z
  KC0_129_W
  KC0_129_X
  KC0_129_XYZW
  KC0_129_Y
  KC0_129_Z

The diff lists do not work correctly because different kinds of registers have
different 'scaling factors'.  This new algorithm, LessRecordRegister, tries to
enforce a scaling factor of 1.  For example, the registers are now sorted as
follows:

  T1
  T2
  T3
  ...
  T0_W
  T1_W
  T2_W
  ...
  T0_X
  T1_X
  T2_X
  ...
  KC0_128_W
  KC0_129_W
  KC0_130_W
  ...

For the Mips and R600 I see a 19% and 6% reduction in size, respectively.  I
did see a few small regressions, but the differences were on the order of a
few bytes (e.g., AArch64 was 16 bytes).  I suspect there will be even
greater wins for targets with larger register files.

Patch reviewed by Jakob.
rdar://14006013


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@185094 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 18 insertions, 18 deletions

diff --git a/test/MC/ARM/basic-arm-instructions.s b/test/MC/ARM/basic-arm-instructions.s
index a7c54ff..aaff80c 100644
--- a/test/MC/ARM/basic-arm-instructions.s
+++ b/test/MC/ARM/basic-arm-instructions.s
@@ -897,17 +897,17 @@ Lforward:
         ldm r0, {r0, r2, lr}^
         ldm sp!, {r0-r3, pc}^
 
-@ CHECK: ldm   r2, {r1, r3, r4, r5, r6, sp} @ encoding: [0x7a,0x20,0x92,0xe8]
-@ CHECK: ldm   r2, {r1, r3, r4, r5, r6, sp} @ encoding: [0x7a,0x20,0x92,0xe8]
-@ CHECK: ldmib r2, {r1, r3, r4, r5, r6, sp} @ encoding: [0x7a,0x20,0x92,0xe9]
-@ CHECK: ldmda r2, {r1, r3, r4, r5, r6, sp} @ encoding: [0x7a,0x20,0x12,0xe8]
-@ CHECK: ldmdb r2, {r1, r3, r4, r5, r6, sp} @ encoding: [0x7a,0x20,0x12,0xe9]
-@ CHECK: ldm   r2, {r1, r3, r4, r5, r6, sp} @ encoding: [0x7a,0x20,0x92,0xe8]
-
-@ CHECK: ldm   r2!, {r1, r3, r4, r5, r6, sp} @ encoding: [0x7a,0x20,0xb2,0xe8]
-@ CHECK: ldmib r2!, {r1, r3, r4, r5, r6, sp} @ encoding: [0x7a,0x20,0xb2,0xe9]
-@ CHECK: ldmda r2!, {r1, r3, r4, r5, r6, sp} @ encoding: [0x7a,0x20,0x32,0xe8]
-@ CHECK: ldmdb r2!, {r1, r3, r4, r5, r6, sp} @ encoding: [0x7a,0x20,0x32,0xe9]
+@ CHECK: ldm   r2, {sp, r1, r3, r4, r5, r6} @ encoding: [0x7a,0x20,0x92,0xe8]
+@ CHECK: ldm   r2, {sp, r1, r3, r4, r5, r6} @ encoding: [0x7a,0x20,0x92,0xe8]
+@ CHECK: ldmib r2, {sp, r1, r3, r4, r5, r6} @ encoding: [0x7a,0x20,0x92,0xe9]
+@ CHECK: ldmda r2, {sp, r1, r3, r4, r5, r6} @ encoding: [0x7a,0x20,0x12,0xe8]
+@ CHECK: ldmdb r2, {sp, r1, r3, r4, r5, r6} @ encoding: [0x7a,0x20,0x12,0xe9]
+@ CHECK: ldm   r2, {sp, r1, r3, r4, r5, r6} @ encoding: [0x7a,0x20,0x92,0xe8]
+
+@ CHECK: ldm   r2!, {sp, r1, r3, r4, r5, r6} @ encoding: [0x7a,0x20,0xb2,0xe8]
+@ CHECK: ldmib r2!, {sp, r1, r3, r4, r5, r6} @ encoding: [0x7a,0x20,0xb2,0xe9]
+@ CHECK: ldmda r2!, {sp, r1, r3, r4, r5, r6} @ encoding: [0x7a,0x20,0x32,0xe8]
+@ CHECK: ldmdb r2!, {sp, r1, r3, r4, r5, r6} @ encoding: [0x7a,0x20,0x32,0xe9]
 @ CHECK: ldm	r0, {lr, r0, r2} ^          @ encoding: [0x05,0x40,0xd0,0xe8]
 @ CHECK: ldm	sp!, {pc, r0, r1, r2, r3} ^ @ encoding: [0x0f,0x80,0xfd,0xe8]
 
@@ -2332,17 +2332,17 @@ Lforward:
         stmda     sp!, {r1,r3-r6}
         stmdb     r0!, {r1,r5,r7,sp}
 
-@ CHECK: stm	r2, {r1, r3, r4, r5, r6, sp} @ encoding: [0x7a,0x20,0x82,0xe8]
+@ CHECK: stm	r2, {sp, r1, r3, r4, r5, r6} @ encoding: [0x7a,0x20,0x82,0xe8]
 @ CHECK: stm	r3, {lr, r1, r3, r4, r5, r6} @ encoding: [0x7a,0x40,0x83,0xe8]
-@ CHECK: stmib	r4, {r1, r3, r4, r5, r6, sp} @ encoding: [0x7a,0x20,0x84,0xe9]
-@ CHECK: stmda	r5, {r1, r3, r4, r5, r6, sp} @ encoding: [0x7a,0x20,0x05,0xe8]
+@ CHECK: stmib	r4, {sp, r1, r3, r4, r5, r6} @ encoding: [0x7a,0x20,0x84,0xe9]
+@ CHECK: stmda	r5, {sp, r1, r3, r4, r5, r6} @ encoding: [0x7a,0x20,0x05,0xe8]
 @ CHECK: stmdb	r6, {r1, r3, r4, r5, r6, r8} @ encoding: [0x7a,0x01,0x06,0xe9]
-@ CHECK: stmdb	sp, {r1, r3, r4, r5, r6, sp} @ encoding: [0x7a,0x20,0x0d,0xe9]
+@ CHECK: stmdb	sp, {sp, r1, r3, r4, r5, r6} @ encoding: [0x7a,0x20,0x0d,0xe9]
 
-@ CHECK: stm	r8!, {r1, r3, r4, r5, r6, sp} @ encoding: [0x7a,0x20,0xa8,0xe8]
-@ CHECK: stmib	r9!, {r1, r3, r4, r5, r6, sp} @ encoding: [0x7a,0x20,0xa9,0xe9]
+@ CHECK: stm	r8!, {sp, r1, r3, r4, r5, r6} @ encoding: [0x7a,0x20,0xa8,0xe8]
+@ CHECK: stmib	r9!, {sp, r1, r3, r4, r5, r6} @ encoding: [0x7a,0x20,0xa9,0xe9]
 @ CHECK: stmda	sp!, {r1, r3, r4, r5, r6}     @ encoding: [0x7a,0x00,0x2d,0xe8]
-@ CHECK: stmdb	r0!, {r1, r5, r7, sp}         @ encoding: [0xa2,0x20,0x20,0xe9]
+@ CHECK: stmdb	r0!, {sp, r1, r5, r7}         @ encoding: [0xa2,0x20,0x20,0xe9]
 
 
 @------------------------------------------------------------------------------