x86: Improve -malign-branch

According to intel SDM manual, not all compare flag-modifying instructions
are marcro-fusible with subsequent jcc instructions. For those non-fusible
instructions, -malign-branch doesn't need to align them, only jcc itself
needs to be aligned.

Here are 2 restrictions which separate macro-fusible instruction from not

Restriction 1:
If TEST/AND/CMP/ADD/SUB/INC/DEC is one of the following format:

   cmp m, imm
   add m, imm
   sub m, imm
   test m, imm
   and m, imm
   inc m
   dec m

it is unfusible with any jcc instruction.

Restriction 2:

/* Table 3-2. Macro-Fusible Instructions in Haswell Microarchitecture
   Note it also works for Skylake and Cascadelake.
---------------------------------------------------------------------
|   JCC   | ADD/SUB/CMP | INC/DEC | TEST/AND |
| ------  | ----------- | ------- | -------- |
|   Jo    |      N      |    N    |     Y    |
|   Jno   |      N      |    N    |     Y    |
|  Jc/Jb  |      Y      |    N    |     Y    |
| Jae/Jnb |      Y      |    N    |     Y    |
|  Je/Jz  |      Y      |    Y    |     Y    |
| Jne/Jnz |      Y      |    Y    |     Y    |
| Jna/Jbe |      Y      |    N    |     Y    |
| Ja/Jnbe |      Y      |    N    |     Y    |
|   Js    |      N      |    N    |     Y    |
|   Jns   |      N      |    N    |     Y    |
|  Jp/Jpe |      N      |    N    |     Y    |
| Jnp/Jpo |      N      |    N    |     Y    |
| Jl/Jnge |      Y      |    Y    |     Y    |
| Jge/Jnl |      Y      |    Y    |     Y    |
| Jle/Jng |      Y      |    Y    |     Y    |
| Jg/Jnle |      Y      |    Y    |     Y    |

Update maybe_fused_with_jcc_p to check if operands of CMP like instructions
can be fused with condition jump.

	* gas/config/tc-i386.h (i386_tc_frag_data): Add member mf_type.
	(TC_FRAG_INIT): Init mf_type.
	* gas/config/tc-i386.c (enum mf_jcc_kind): New enum.
	(enum mf_cmp_kind): Ditto.
	(maybe_fused_with_jcc_p): Add argument mf_cmp_p to get
	mf_type of corresponding instructons, exclude unfusible
	instructions.
	(add_fused_jcc_padding_frag_p): Likewise.
	(add_branch_padding_frag_p): Likewise.
	(output_insn): Record mf_type for corresponding instructions.
	(i386_macro_fusible_p): New function.
	(i386_next_fusible_jcc_frag): Rename from i386_next_jcc_frag,
	add argument cmp_fragP to return next fusible jcc frag only.
	(i386_classify_machine_dependant_frag): Seperate macro-fusible
	instructions from condition jump.
	* gas/testsuite/gas/i386/align-branch-9.s: New file.
	* gas/testsuite/gas/i386/align-branch-9.d: Ditto.
	* gas/testsuite/gas/i386/x86-64-align-branch-9.s: Ditto.
	* gas/testsuite/gas/i386/x86-64-align-branch-9.d: Ditto.
	* gas/testsuite/gas/i386/i386.exp: Run new tests.

5 files changed, 243 insertions, 0 deletions

diff --git a/gas/testsuite/gas/i386/align-branch-9.d b/gas/testsuite/gas/i386/align-branch-9.d
new file mode 100644
index 0000000..6340817
--- /dev/null
+++ b/gas/testsuite/gas/i386/align-branch-9.d
@@ -0,0 +1,78 @@
+#as: -mbranches-within-32B-boundaries
+#objdump: -dw
+
+.*: +file format .*
+
+Disassembly of section .text:
+
+0+ <foo>:
+   0:	65 a3 01 00 00 00    	mov    %eax,%gs:0x1
+   6:	55                   	push   %ebp
+   7:	55                   	push   %ebp
+   8:	55                   	push   %ebp
+   9:	55                   	push   %ebp
+   a:	89 e5                	mov    %esp,%ebp
+   c:	89 7d f8             	mov    %edi,-0x8\(%ebp\)
+   f:	89 75 f4             	mov    %esi,-0xc\(%ebp\)
+  12:	89 75 f4             	mov    %esi,-0xc\(%ebp\)
+  15:	89 75 f4             	mov    %esi,-0xc\(%ebp\)
+  18:	89 75 f4             	mov    %esi,-0xc\(%ebp\)
+  1b:	89 75 f4             	mov    %esi,-0xc\(%ebp\)
+  1e:	39 c5                	cmp    %eax,%ebp
+  20:	70 62                	jo     84 <foo\+0x84>
+  22:	89 73 f4             	mov    %esi,-0xc\(%ebx\)
+  25:	89 75 f4             	mov    %esi,-0xc\(%ebp\)
+  28:	89 7d f8             	mov    %edi,-0x8\(%ebp\)
+  2b:	89 75 f4             	mov    %esi,-0xc\(%ebp\)
+  2e:	89 75 f4             	mov    %esi,-0xc\(%ebp\)
+  31:	89 75 f4             	mov    %esi,-0xc\(%ebp\)
+  34:	89 75 f4             	mov    %esi,-0xc\(%ebp\)
+  37:	89 75 f4             	mov    %esi,-0xc\(%ebp\)
+  3a:	5d                   	pop    %ebp
+  3b:	5d                   	pop    %ebp
+  3c:	5d                   	pop    %ebp
+  3d:	74 45                	je     84 <foo\+0x84>
+  3f:	5d                   	pop    %ebp
+  40:	74 42                	je     84 <foo\+0x84>
+  42:	89 44 24 fc          	mov    %eax,-0x4\(%esp\)
+  46:	89 75 f4             	mov    %esi,-0xc\(%ebp\)
+  49:	89 7d f8             	mov    %edi,-0x8\(%ebp\)
+  4c:	89 75 f4             	mov    %esi,-0xc\(%ebp\)
+  4f:	89 75 f4             	mov    %esi,-0xc\(%ebp\)
+  52:	89 75 f4             	mov    %esi,-0xc\(%ebp\)
+  55:	89 75 f4             	mov    %esi,-0xc\(%ebp\)
+  58:	89 75 f4             	mov    %esi,-0xc\(%ebp\)
+  5b:	5d                   	pop    %ebp
+  5c:	eb 2c                	jmp    8a <foo\+0x8a>
+  5e:	66 90                	xchg   %ax,%ax
+  60:	eb 28                	jmp    8a <foo\+0x8a>
+  62:	eb 26                	jmp    8a <foo\+0x8a>
+  64:	89 45 fc             	mov    %eax,-0x4\(%ebp\)
+  67:	89 75 f4             	mov    %esi,-0xc\(%ebp\)
+  6a:	89 7d f8             	mov    %edi,-0x8\(%ebp\)
+  6d:	5d                   	pop    %ebp
+  6e:	5d                   	pop    %ebp
+  6f:	40                   	inc    %eax
+  70:	72 12                	jb     84 <foo\+0x84>
+  72:	36 36 89 45 fc       	ss mov %eax,%ss:-0x4\(%ebp\)
+  77:	89 75 f4             	mov    %esi,-0xc\(%ebp\)
+  7a:	89 7d f8             	mov    %edi,-0x8\(%ebp\)
+  7d:	89 75 f4             	mov    %esi,-0xc\(%ebp\)
+  80:	21 c3                	and    %eax,%ebx
+  82:	7c 06                	jl     8a <foo\+0x8a>
+  84:	8b 45 f4             	mov    -0xc\(%ebp\),%eax
+  87:	89 45 fc             	mov    %eax,-0x4\(%ebp\)
+  8a:	89 b5 50 fb ff ff    	mov    %esi,-0x4b0\(%ebp\)
+  90:	89 b5 50 fb ff ff    	mov    %esi,-0x4b0\(%ebp\)
+  96:	89 b5 50 fb ff ff    	mov    %esi,-0x4b0\(%ebp\)
+  9c:	89 b5 50 fb ff ff    	mov    %esi,-0x4b0\(%ebp\)
+  a2:	89 75 0c             	mov    %esi,0xc\(%ebp\)
+  a5:	e9 fc ff ff ff       	jmp    a6 <foo\+0xa6>
+  aa:	89 b5 50 fb ff ff    	mov    %esi,-0x4b0\(%ebp\)
+  b0:	89 b5 50 fb ff ff    	mov    %esi,-0x4b0\(%ebp\)
+  b6:	89 b5 50 fb ff ff    	mov    %esi,-0x4b0\(%ebp\)
+  bc:	89 b5 50 fb ff ff    	mov    %esi,-0x4b0\(%ebp\)
+  c2:	89 75 00             	mov    %esi,0x0\(%ebp\)
+  c5:	74 c3                	je     8a <foo\+0x8a>
+  c7:	74 c1                	je     8a <foo\+0x8a>
+#pass
diff --git a/gas/testsuite/gas/i386/align-branch-9.s b/gas/testsuite/gas/i386/align-branch-9.s
new file mode 100644
index 0000000..357abe3
--- /dev/null
+++ b/gas/testsuite/gas/i386/align-branch-9.s
@@ -0,0 +1,74 @@
+  .text
+  .globl  foo
+  .p2align  4
+foo:
+  movl	%eax, %gs:0x1
+  pushl  %ebp
+  pushl  %ebp
+  pushl  %ebp
+  pushl  %ebp
+  movl  %esp, %ebp
+  movl  %edi, -8(%ebp)
+  movl  %esi, -12(%ebp)
+  movl  %esi, -12(%ebp)
+  movl  %esi, -12(%ebp)
+  movl  %esi, -12(%ebp)
+  movl  %esi, -12(%ebp)
+  cmp  %eax, %ebp
+  jo  .L_2
+  movl  %esi, -12(%ebx)
+  movl  %esi, -12(%ebp)
+  movl  %edi, -8(%ebp)
+  movl  %esi, -12(%ebp)
+  movl  %esi, -12(%ebp)
+  movl  %esi, -12(%ebp)
+  movl  %esi, -12(%ebp)
+  movl  %esi, -12(%ebp)
+  popl  %ebp
+  popl  %ebp
+  popl  %ebp
+  je  .L_2
+  popl  %ebp
+  je  .L_2
+  movl  %eax, -4(%esp)
+  movl  %esi, -12(%ebp)
+  movl  %edi, -8(%ebp)
+  movl  %esi, -12(%ebp)
+  movl  %esi, -12(%ebp)
+  movl  %esi, -12(%ebp)
+  movl  %esi, -12(%ebp)
+  movl  %esi, -12(%ebp)
+  popl  %ebp
+  jmp  .L_3
+  jmp  .L_3
+  jmp  .L_3
+  movl  %eax, -4(%ebp)
+  movl  %esi, -12(%ebp)
+  movl  %edi, -8(%ebp)
+  popl  %ebp
+  popl  %ebp
+  inc  %eax
+  jc  .L_2
+  movl  %eax, -4(%ebp)
+  movl  %esi, -12(%ebp)
+  movl  %edi, -8(%ebp)
+  movl  %esi, -12(%ebp)
+  and  %eax, %ebx
+  jl  .L_3
+.L_2:
+  movl  -12(%ebp), %eax
+  movl  %eax, -4(%ebp)
+.L_3:
+  movl  %esi, -1200(%ebp)
+  movl  %esi, -1200(%ebp)
+  movl  %esi, -1200(%ebp)
+  movl  %esi, -1200(%ebp)
+  movl  %esi, 12(%ebp)
+  jmp  bar
+  movl  %esi, -1200(%ebp)
+  movl  %esi, -1200(%ebp)
+  movl  %esi, -1200(%ebp)
+  movl  %esi, -1200(%ebp)
+  movl  %esi, (%ebp)
+  je .L_3
+  je .L_3
diff --git a/gas/testsuite/gas/i386/i386.exp b/gas/testsuite/gas/i386/i386.exp
index 685e62e..8fc621f 100644
--- a/gas/testsuite/gas/i386/i386.exp
+++ b/gas/testsuite/gas/i386/i386.exp
@@ -525,6 +525,7 @@ if [expr ([istarget "i*86-*-*"] ||  [istarget "x86_64-*-*"]) && [gas_32_check]]
     run_dump_test "align-branch-6"
     run_dump_test "align-branch-7"
     run_dump_test "align-branch-8"
+    run_dump_test "align-branch-9"
 
     # These tests require support for 8 and 16 bit relocs,
     # so we only run them for ELF and COFF targets.
@@ -1100,6 +1101,7 @@ if [expr ([istarget "i*86-*-*"] || [istarget "x86_64-*-*"]) && [gas_64_check]] t
     run_dump_test "x86-64-align-branch-6"
     run_dump_test "x86-64-align-branch-7"
     run_dump_test "x86-64-align-branch-8"
+    run_dump_test "x86-64-align-branch-9"
 
     if { ![istarget "*-*-aix*"]
       && ![istarget "*-*-beos*"]
diff --git a/gas/testsuite/gas/i386/x86-64-align-branch-9.d b/gas/testsuite/gas/i386/x86-64-align-branch-9.d
new file mode 100644
index 0000000..1041fd0
--- /dev/null
+++ b/gas/testsuite/gas/i386/x86-64-align-branch-9.d
@@ -0,0 +1,46 @@
+#as: -mbranches-within-32B-boundaries
+#objdump: -dw
+
+.*: +file format .*
+
+Disassembly of section .text:
+
+0+ <foo>:
+   0:	c1 e9 02             	shr    \$0x2,%ecx
+   3:	c1 e9 02             	shr    \$0x2,%ecx
+   6:	c1 e9 02             	shr    \$0x2,%ecx
+   9:	89 d1                	mov    %edx,%ecx
+   b:	31 c0                	xor    %eax,%eax
+   d:	c1 e9 02             	shr    \$0x2,%ecx
+  10:	c1 e9 02             	shr    \$0x2,%ecx
+  13:	c1 e9 02             	shr    \$0x2,%ecx
+  16:	c1 e9 02             	shr    \$0x2,%ecx
+  19:	c1 e9 02             	shr    \$0x2,%ecx
+  1c:	c1 e9 02             	shr    \$0x2,%ecx
+  1f:	80 fa 02             	cmp    \$0x2,%dl
+  22:	70 df                	jo     3 <foo\+0x3>
+  24:	2e 2e 2e 2e 31 c0    	cs cs cs cs xor %eax,%eax
+  2a:	c1 e9 02             	shr    \$0x2,%ecx
+  2d:	c1 e9 02             	shr    \$0x2,%ecx
+  30:	c1 e9 02             	shr    \$0x2,%ecx
+  33:	89 d1                	mov    %edx,%ecx
+  35:	31 c0                	xor    %eax,%eax
+  37:	c1 e9 02             	shr    \$0x2,%ecx
+  3a:	c1 e9 02             	shr    \$0x2,%ecx
+  3d:	c1 e9 02             	shr    \$0x2,%ecx
+  40:	f6 c2 02             	test   \$0x2,%dl
+  43:	75 e8                	jne    2d <foo\+0x2d>
+  45:	31 c0                	xor    %eax,%eax
+  47:	c1 e9 02             	shr    \$0x2,%ecx
+  4a:	c1 e9 02             	shr    \$0x2,%ecx
+  4d:	89 d1                	mov    %edx,%ecx
+  4f:	c1 e9 02             	shr    \$0x2,%ecx
+  52:	c1 e9 02             	shr    \$0x2,%ecx
+  55:	89 d1                	mov    %edx,%ecx
+  57:	c1 e9 02             	shr    \$0x2,%ecx
+  5a:	89 d1                	mov    %edx,%ecx
+  5c:	31 c0                	xor    %eax,%eax
+  5e:	ff c0                	inc    %eax
+  60:	76 cb                	jbe    2d <foo\+0x2d>
+  62:	31 c0                	xor    %eax,%eax
+#pass
diff --git a/gas/testsuite/gas/i386/x86-64-align-branch-9.s b/gas/testsuite/gas/i386/x86-64-align-branch-9.s
new file mode 100644
index 0000000..917579b
--- /dev/null
+++ b/gas/testsuite/gas/i386/x86-64-align-branch-9.s
@@ -0,0 +1,43 @@
+	.text
+	.p2align 4,,15
+foo:
+	shrl	$2, %ecx
+.L1:
+	shrl	$2, %ecx
+	shrl	$2, %ecx
+	movl	%edx, %ecx
+	xorl	%eax, %eax
+	shrl	$2, %ecx
+	shrl	$2, %ecx
+	shrl	$2, %ecx
+	shrl	$2, %ecx
+	shrl	$2, %ecx
+	shrl	$2, %ecx
+	cmpb	$2, %dl
+	jo	.L1
+	xorl	%eax, %eax
+	shrl	$2, %ecx
+.L2:
+	shrl	$2, %ecx
+	shrl	$2, %ecx
+	movl	%edx, %ecx
+	xorl	%eax, %eax
+	shrl	$2, %ecx
+	shrl	$2, %ecx
+	shrl	$2, %ecx
+	testb	$2, %dl
+	jne	.L2
+	xorl	%eax, %eax
+.L3:
+	shrl	$2, %ecx
+	shrl	$2, %ecx
+	movl	%edx, %ecx
+	shrl	$2, %ecx
+	shrl	$2, %ecx
+	movl	%edx, %ecx
+	shrl	$2, %ecx
+	movl	%edx, %ecx
+	xorl	%eax, %eax
+	inc	%eax
+	jbe	.L2
+	xorl	%eax, %eax