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cmd/internal/obj/arm64: fix encoding of AND MBCON

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When a constant is both MOVCON (can fit into a MOV instruction)
and BITCON (can fit into a logical instruction), the assembler
chooses to use the MOVCON encoding, which is actually longer for
logical instructions. We add MBCON rules explicitly to make sure
it uses the BITCON encoding.

Updates #19857.

Change-Id: Ib9881be363cbc491ac2a0792b36b87e74eff34a8
Reviewed-on: https://go-review.googlesource.com/39652
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>
This commit is contained in:
Cherry Zhang 2017-04-06 10:01:36 -04:00
parent 257b01f8f4
commit 0bae9b083b
3 changed files with 19 additions and 3 deletions
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9
src/cmd/asm/internal/asm/testdata/arm64.s vendored
View File

@ -45,6 +45,15 @@ TEXT foo(SB), 7, $-8
ADD R1->33, R2
AND R1@>33, R2
// logical ops
// make sure constants get encoded into an instruction when it could
AND $(1<<63), R1 // AND $-9223372036854775808, R1 // 21004192
AND $(1<<63-1), R1 // AND $9223372036854775807, R1 // 21f84092
ORR $(1<<63), R1 // ORR $-9223372036854775808, R1 // 210041b2
ORR $(1<<63-1), R1 // ORR $9223372036854775807, R1 // 21f840b2
EOR $(1<<63), R1 // EOR $-9223372036854775808, R1 // 210041d2
EOR $(1<<63-1), R1 // EOR $9223372036854775807, R1 // 21f840d2
//
// CLS
//

9
src/cmd/internal/obj/arm64/a.out.go
View File

@ -254,6 +254,9 @@ const (
)
const (
// optab is sorted based on the order of these constants
// and the first match is chosen.
// The more specific class needs to come earlier.
C_NONE = iota
C_REG // R0..R30
C_RSP // R0..R30, RSP
@ -266,13 +269,13 @@ const (
C_COND // EQ, NE, etc
C_ZCON // $0 or ZR
C_ABCON0 // could be C_ADDCON0 or C_BITCON
C_ADDCON0 // 12-bit unsigned, unshifted
C_ABCON // could be C_ADDCON or C_BITCON
C_ADDCON // 12-bit unsigned, shifted left by 0 or 12
C_MBCON // could be C_MOVCON or C_BITCON
C_MOVCON // generated by a 16-bit constant, optionally inverted and/or shifted by multiple of 16
C_BITCON // bitfield and logical immediate masks
C_ABCON0 // could be C_ADDCON0 or C_BITCON
C_ABCON // could be C_ADDCON or C_BITCON
C_MBCON // could be C_MOVCON or C_BITCON
C_LCON // 32-bit constant
C_VCON // 64-bit constant
C_FCON // floating-point constant

4
src/cmd/internal/obj/arm64/asm7.go
View File

@ -190,6 +190,10 @@ var optab = []Optab{
{AAND, C_REG, C_NONE, C_REG, 1, 4, 0, 0, 0},
{ABIC, C_REG, C_REG, C_REG, 1, 4, 0, 0, 0},
{ABIC, C_REG, C_NONE, C_REG, 1, 4, 0, 0, 0},
{AAND, C_MBCON, C_REG, C_REG, 53, 4, 0, 0, 0},
{AAND, C_MBCON, C_NONE, C_REG, 53, 4, 0, 0, 0},
{ABIC, C_MBCON, C_REG, C_REG, 53, 4, 0, 0, 0},
{ABIC, C_MBCON, C_NONE, C_REG, 53, 4, 0, 0, 0},
{AAND, C_BITCON, C_REG, C_REG, 53, 4, 0, 0, 0},
{AAND, C_BITCON, C_NONE, C_REG, 53, 4, 0, 0, 0},
{ABIC, C_BITCON, C_REG, C_REG, 53, 4, 0, 0, 0},