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Re: [PATCH] [GAS, ARM] Invalid LDR immediate transformation
- From: Christophe Lyon <christophe dot lyon at linaro dot org>
- To: Nick Clifton <nickc at redhat dot com>
- Cc: Christophe MONAT <christophe dot monat at st dot com>, "binutils at sourceware dot org" <binutils at sourceware dot org>
- Date: Tue, 24 Nov 2015 22:27:52 +0100
- Subject: Re: [PATCH] [GAS, ARM] Invalid LDR immediate transformation
- Authentication-results: sourceware.org; auth=none
- References: <56532CF5 dot 5070300 at st dot com> <5654866D dot 80105 at redhat dot com>
On 24 November 2015 at 16:46, Nick Clifton <nickc@redhat.com> wrote:
> Hi Christophe,
>
>> I have attached a patch, tested on an x86_64 host in arm-none-eabi
>> arm-linux-eabi arm-nacl, no regression.
>
>
> This patch is approved for the mainline.
>
I've commit it on Christophe's behalf.
It needed a small adjustment in the testcase after a recent fix from Matthew
in the same area.
I've attached what I have committed.
I hope I did it right (commit message), since it's my first commit in binutils
since we switched to git :-)
> It probably should go into the 2.26 branch as well, but please check with
> Tristan first.
>
Since Matthew's patch is in the 2.26 branch too, we need the updated
testcase if this patch is OK for 2.26. Tristan?
Thanks,
Christophe.
> Cheers
> Nick
>
>
commit 2c32be708da9011b3ce7404f2be43b17ab1eddd4
Author: Christophe Monat <christophe.monat@st.com>
Date: Tue Nov 24 22:17:54 2015 +0100
[GAS, ARM] Invalid LDR immediate transformation
2015-11-24 Christophe Monat <christophe.monat@st.com>
* config/tc-arm.c (move_or_literal_pool): Do not transform ldr
ri,=imm into movs when ri is a high register in T1.
2015-11-24 Christophe Monat <christophe.monat@st.com>
* gas/arm/thumb2_ldr_immediate_armv6t2.s: Added high register
tests.
* gas/arm/thumb2_ldr_immediate_armv6t2.d: Accounted for new test
cases.
* gas/arm/thumb2_ldr_immediate_highregs_armv6t2.s: New.
* gas/arm/thumb2_ldr_immediate_highregs_armv6t2.d: New.
diff --git a/gas/ChangeLog b/gas/ChangeLog
index bec87cf..1077066 100644
--- a/gas/ChangeLog
+++ b/gas/ChangeLog
@@ -1,3 +1,8 @@
+2015-11-24 Christophe Monat <christophe.monat@st.com>
+
+ * config/tc-arm.c (move_or_literal_pool): Do not transform ldr
+ ri,=imm into movs when ri is a high register in T1.
+
2015-11-20 Nick Clifton <nickc@redhat.com>
* po/fr.po: Updated French translation.
diff --git a/gas/config/tc-arm.c b/gas/config/tc-arm.c
index 23c506d..8ea1e8d 100644
--- a/gas/config/tc-arm.c
+++ b/gas/config/tc-arm.c
@@ -7839,7 +7839,8 @@ move_or_literal_pool (int i, enum lit_type t, bfd_boolean mode_3)
{
if (thumb_p)
{
- if ((v & ~0xFF) == 0)
+ /* This can be encoded only for a low register. */
+ if ((v & ~0xFF) == 0 && (inst.operands[i].reg < 8))
{
/* This can be done with a mov(1) instruction. */
inst.instruction = T_OPCODE_MOV_I8 | (inst.operands[i].reg << 8);
diff --git a/gas/testsuite/ChangeLog b/gas/testsuite/ChangeLog
index a38fc25..aae4691 100644
--- a/gas/testsuite/ChangeLog
+++ b/gas/testsuite/ChangeLog
@@ -1,3 +1,12 @@
+2015-11-24 Christophe Monat <christophe.monat@st.com>
+
+ * gas/arm/thumb2_ldr_immediate_armv6t2.s: Added high register
+ tests.
+ * gas/arm/thumb2_ldr_immediate_armv6t2.d: Accounted for new test
+ cases.
+ * gas/arm/thumb2_ldr_immediate_highregs_armv6t2.s: New.
+ * gas/arm/thumb2_ldr_immediate_highregs_armv6t2.d: New.
+
2015-11-24 Matthew Wahab <matthew.wahab@arm.com>
* gas/arm/armv7e-m+fpv5-d16.d: Skip test for *-*-pe, *-wince-* and
diff --git a/gas/testsuite/gas/arm/thumb2_ldr_immediate_armv6t2.d b/gas/testsuite/gas/arm/thumb2_ldr_immediate_armv6t2.d
index 6897bcd..09c46a8 100644
--- a/gas/testsuite/gas/arm/thumb2_ldr_immediate_armv6t2.d
+++ b/gas/testsuite/gas/arm/thumb2_ldr_immediate_armv6t2.d
@@ -1,4 +1,4 @@
-# name: Ldr immediate on armv6
+# name: Ldr immediate on armv6t2
# as: -march=armv6t2
# objdump: -dr --prefix-addresses --show-raw-insn
#skip: *-*-pe *-wince-* *-*-coff
@@ -10,7 +10,13 @@ Disassembly of section .text:
0[0-9a-f]+ <[^>]+> f04f 2163 mov.w r1, #1660969728 .*
0[0-9a-f]+ <[^>]+> f04f 1151 mov.w r1, #5308497 .*
0[0-9a-f]+ <[^>]+> f44f 228e mov.w r2, #290816 .*
-0[0-9a-f]+ <[^>]+> 4a01 ldr r2, \[pc, #4\] .*
+0[0-9a-f]+ <[^>]+> 4a07 ldr r2, \[pc, #28\] .*
0[0-9a-f]+ <[^>]+> f241 32f1 movw r2, #5105 .*
+0[0-9a-f]+ <[^>]+> f04f 3872 mov.w r8, #1920103026 .*
+0[0-9a-f]+ <[^>]+> f04f 2863 mov.w r8, #1660969728 .*
+0[0-9a-f]+ <[^>]+> f04f 1851 mov.w r8, #5308497 .*
+0[0-9a-f]+ <[^>]+> f44f 298e mov.w r9, #290816 .*
+0[0-9a-f]+ <[^>]+> f8df 9008 ldr.w r9, \[pc, #8\] .*
+0[0-9a-f]+ <[^>]+> f241 39f1 movw r9, #5105 .*
0[0-9a-f]+ <[^>]+> 0000 .short 0x0000
0[0-9a-f]+ <[^>]+> ff320000 .word 0xff320000
diff --git a/gas/testsuite/gas/arm/thumb2_ldr_immediate_armv6t2.s b/gas/testsuite/gas/arm/thumb2_ldr_immediate_armv6t2.s
index 22a5014..4b94c91 100644
--- a/gas/testsuite/gas/arm/thumb2_ldr_immediate_armv6t2.s
+++ b/gas/testsuite/gas/arm/thumb2_ldr_immediate_armv6t2.s
@@ -9,4 +9,10 @@ thumb2_ldr:
ldr r2,=0x00047000
ldr r2,=0xFF320000
ldr r2,=0x000013F1
+ ldr r8,=0x72727272
+ ldr r8,=0x63006300
+ ldr r8,=0x00510051
+ ldr r9,=0x00047000
+ ldr r9,=0xFF320000
+ ldr r9,=0x000013F1
.pool
diff --git a/gas/testsuite/gas/arm/thumb2_ldr_immediate_highregs_armv6t2.d b/gas/testsuite/gas/arm/thumb2_ldr_immediate_highregs_armv6t2.d
new file mode 100644
index 0000000..55b5f17
--- /dev/null
+++ b/gas/testsuite/gas/arm/thumb2_ldr_immediate_highregs_armv6t2.d
@@ -0,0 +1,24 @@
+# name: Ldr small immediate high registers on armv6t2
+# as: -march=armv6t2
+# objdump: -dr --prefix-addresses --show-raw-insn
+# not-target: *-*-*coff *-*-pe *-*-wince *-*-*aout* *-*-netbsd *-*-riscix*
+
+.*: +file format .*arm.*
+
+Disassembly of section \.text:
+0[0-9a-f]+ <[^>]+> 2000[[:space:]]+movs[[:space:]]+r0, #0.*
+0[0-9a-f]+ <[^>]+> 2108[[:space:]]+movs[[:space:]]+r1, #8.*
+0[0-9a-f]+ <[^>]+> 2251[[:space:]]+movs[[:space:]]+r2, #81.*
+0[0-9a-f]+ <[^>]+> 231f[[:space:]]+movs[[:space:]]+r3, #31.*
+0[0-9a-f]+ <[^>]+> 242f[[:space:]]+movs[[:space:]]+r4, #47.*
+0[0-9a-f]+ <[^>]+> 253f[[:space:]]+movs[[:space:]]+r5, #63.*
+0[0-9a-f]+ <[^>]+> 2680[[:space:]]+movs[[:space:]]+r6, #128.*
+0[0-9a-f]+ <[^>]+> 27ff[[:space:]]+movs[[:space:]]+r7, #255.*
+0[0-9a-f]+ <[^>]+> f04f 0800[[:space:]]+mov\.w[[:space:]]+r8, #0.*
+0[0-9a-f]+ <[^>]+> f04f 0908[[:space:]]+mov\.w[[:space:]]+r9, #8.*
+0[0-9a-f]+ <[^>]+> f04f 0a51[[:space:]]+mov\.w[[:space:]]+sl, #81.*
+0[0-9a-f]+ <[^>]+> f04f 0b1f[[:space:]]+mov\.w[[:space:]]+fp, #31.*
+0[0-9a-f]+ <[^>]+> f04f 0c2f[[:space:]]+mov\.w[[:space:]]+ip, #47.*
+0[0-9a-f]+ <[^>]+> f04f 0d3f[[:space:]]+mov\.w[[:space:]]+sp, #63.*
+0[0-9a-f]+ <[^>]+> f04f 0e80[[:space:]]+mov\.w[[:space:]]+lr, #128.*
+0[0-9a-f]+ <[^>]+> f04f 0fff[[:space:]]+mov\.w[[:space:]]+pc, #255.*
diff --git a/gas/testsuite/gas/arm/thumb2_ldr_immediate_highregs_armv6t2.s b/gas/testsuite/gas/arm/thumb2_ldr_immediate_highregs_armv6t2.s
new file mode 100644
index 0000000..d225410
--- /dev/null
+++ b/gas/testsuite/gas/arm/thumb2_ldr_immediate_highregs_armv6t2.s
@@ -0,0 +1,24 @@
+ .thumb
+ .syntax unified
+ .thumb_func
+thumb2_ldr:
+ # These can be encoded into movs since constant is small
+ # And register can be encoded in 3 bits
+ ldr r0,=0x00
+ ldr r1,=0x08
+ ldr r2,=0x51
+ ldr r3,=0x1F
+ ldr r4,=0x2F
+ ldr r5,=0x3F
+ ldr r6,=0x80
+ ldr r7,=0xFF
+ # These shall be encoded into mov.w
+ # Since register cannot be encoded in 3 bits
+ ldr r8,=0x00
+ ldr r9,=0x08
+ ldr r10,=0x51
+ ldr r11,=0x1F
+ ldr r12,=0x2F
+ ldr r13,=0x3F
+ ldr r14,=0x80
+ ldr r15,=0xFF