[binutils-gdb] aarch64: simplify RCPC3 unpredictable logic
Jan Beulich
jbeulich@sourceware.org
Fri Mar 21 07:35:33 GMT 2025
https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=37a1bbe9d56e0fc6093a687c55023db7d465da86
commit 37a1bbe9d56e0fc6093a687c55023db7d465da86
Author: Jan Beulich <jbeulich@suse.com>
Date: Fri Mar 21 08:33:39 2025 +0100
aarch64: simplify RCPC3 unpredictable logic
The original observation was that STILP is warned about when everything
is fine. Documentation, not just for STILP, says explicitly that
behavior is identical to respective pre-existing insns (for STILP in
particular that's STP). With that it's unclear why distinct logic was
added: Other code can be re-used, simply distinguishing by the number of
operands. This was diagnostics also end up more consistent.
Along with adding some STILP uses to the (positive) testcase, also add a
pair of STLR to similarly demonstrate that the register overlap goes
without warning when there's no write-back.
Diff:
---
gas/config/tc-aarch64.c | 41 ++++---------------------------
gas/testsuite/gas/aarch64/rcpc3-fail.l | 44 ++++++++++++++++------------------
gas/testsuite/gas/aarch64/rcpc3-fail.s | 5 ----
gas/testsuite/gas/aarch64/rcpc3.d | 4 ++++
gas/testsuite/gas/aarch64/rcpc3.s | 4 ++++
5 files changed, 32 insertions(+), 66 deletions(-)
diff --git a/gas/config/tc-aarch64.c b/gas/config/tc-aarch64.c
index 840cf8ce4a2..e071ad11f46 100644
--- a/gas/config/tc-aarch64.c
+++ b/gas/config/tc-aarch64.c
@@ -8465,6 +8465,7 @@ warn_unpredictable_ldst (aarch64_instruction *instr, char *str)
case ldst_imm10:
case ldst_unscaled:
case ldst_unpriv:
+ ldst_single:
/* Loading/storing the base register is unpredictable if writeback. */
if ((aarch64_get_operand_class (opnds[0].type)
== AARCH64_OPND_CLASS_INT_REG)
@@ -8477,43 +8478,9 @@ warn_unpredictable_ldst (aarch64_instruction *instr, char *str)
break;
case rcpc3:
- {
- const int nb_operands = aarch64_num_of_operands (opcode);
- if (aarch64_get_operand_class (opnds[0].type)
- == AARCH64_OPND_CLASS_INT_REG)
- {
- /* Load Pair transfer with register overlap. */
- if (nb_operands == 3 && opnds[0].reg.regno == opnds[1].reg.regno)
- { // ldiapp, stilp
- as_warn (_("unpredictable load pair transfer with register "
- "overlap -- `%s'"),
- str);
- }
- /* Loading/storing the base register is unpredictable if writeback. */
- else if ((nb_operands == 2
- && opnds[0].reg.regno == opnds[1].addr.base_regno
- && opnds[1].addr.base_regno != REG_SP
- && opnds[1].addr.writeback)
- || (nb_operands == 3
- && (opnds[0].reg.regno == opnds[2].addr.base_regno
- || opnds[1].reg.regno == opnds[2].addr.base_regno)
- && opnds[2].addr.base_regno != REG_SP
- && opnds[2].addr.writeback))
- {
- if (strcmp (opcode->name, "ldapr") == 0
- || strcmp (opcode->name, "ldiapp") == 0)
- as_warn (
- _("unpredictable transfer with writeback (load) -- `%s'"),
- str);
- else // stlr, stilp
- as_warn (
- _("unpredictable transfer with writeback (store) -- `%s'"),
- str);
- }
- }
- }
- break;
-
+ if (aarch64_num_of_operands (opcode) == 2)
+ goto ldst_single;
+ /* Fall through. */
case ldstpair_off:
case ldstnapair_offs:
case ldstpair_indexed:
diff --git a/gas/testsuite/gas/aarch64/rcpc3-fail.l b/gas/testsuite/gas/aarch64/rcpc3-fail.l
index 96c2f0aee6c..95987fecbdc 100644
--- a/gas/testsuite/gas/aarch64/rcpc3-fail.l
+++ b/gas/testsuite/gas/aarch64/rcpc3-fail.l
@@ -51,27 +51,23 @@
.*: Error: invalid increment amount at operand 2 -- `stlr x0,\[x1,#-4\]!'
.*: Error: invalid increment amount at operand 2 -- `stlr w0,\[x1,#4\]!'
.*: Error: invalid increment amount at operand 2 -- `stlr x0,\[x1,#8\]!'
-.*: Warning: unpredictable load pair transfer with register overlap -- `ldiapp w0,w0,\[x1\]'
-.*: Warning: unpredictable load pair transfer with register overlap -- `ldiapp x0,x0,\[x1\]'
-.*: Warning: unpredictable load pair transfer with register overlap -- `ldiapp w0,w0,\[x1\],#8'
-.*: Warning: unpredictable load pair transfer with register overlap -- `ldiapp x0,x0,\[x1\],#16'
-.*: Warning: unpredictable load pair transfer with register overlap -- `stilp w0,w0,\[x1\]'
-.*: Warning: unpredictable load pair transfer with register overlap -- `stilp x0,x0,\[x1\]'
-.*: Warning: unpredictable load pair transfer with register overlap -- `stilp w0,w0,\[x1,#-8\]!'
-.*: Warning: unpredictable load pair transfer with register overlap -- `stilp x0,x0,\[x1,#-16\]!'
-.*: Warning: unpredictable transfer with writeback \(load\) -- `ldiapp x0,x1,\[x0\],#16'
-.*: Warning: unpredictable transfer with writeback \(load\) -- `ldiapp x0,x1,\[x1\],#16'
-.*: Warning: unpredictable transfer with writeback \(load\) -- `ldiapp w0,w1,\[x0\],#8'
-.*: Warning: unpredictable transfer with writeback \(load\) -- `ldiapp w0,w1,\[x1\],#8'
-.*: Warning: unpredictable transfer with writeback \(load\) -- `ldapr x0,\[x0\],#8'
-.*: Warning: unpredictable transfer with writeback \(load\) -- `ldapr w0,\[x0\],#4'
-.*: Warning: unpredictable transfer with writeback \(load\) -- `ldapr x1,\[x1\],#8'
-.*: Warning: unpredictable transfer with writeback \(load\) -- `ldapr x30,\[x30\],#8'
-.*: Warning: unpredictable transfer with writeback \(store\) -- `stilp x0,x1,\[x1,#-16\]!'
-.*: Warning: unpredictable transfer with writeback \(store\) -- `stilp w0,w1,\[x1,#-8\]!'
-.*: Warning: unpredictable transfer with writeback \(store\) -- `stilp x0,x1,\[x0,#-16\]!'
-.*: Warning: unpredictable transfer with writeback \(store\) -- `stilp w0,w1,\[x0,#-8\]!'
-.*: Warning: unpredictable transfer with writeback \(store\) -- `stlr x0,\[x0,#-8\]!'
-.*: Warning: unpredictable transfer with writeback \(store\) -- `stlr w0,\[x0,#-4\]!'
-.*: Warning: unpredictable transfer with writeback \(store\) -- `stlr x1,\[x1,#-8\]!'
-.*: Warning: unpredictable transfer with writeback \(store\) -- `stlr x30,\[x30,#-8\]!'
\ No newline at end of file
+.*: Warning: unpredictable load of register pair -- `ldiapp w0,w0,\[x1\]'
+.*: Warning: unpredictable load of register pair -- `ldiapp x0,x0,\[x1\]'
+.*: Warning: unpredictable load of register pair -- `ldiapp w0,w0,\[x1\],#8'
+.*: Warning: unpredictable load of register pair -- `ldiapp x0,x0,\[x1\],#16'
+.*: Warning: unpredictable transfer with writeback -- `ldiapp x0,x1,\[x0\],#16'
+.*: Warning: unpredictable transfer with writeback -- `ldiapp x0,x1,\[x1\],#16'
+.*: Warning: unpredictable transfer with writeback -- `ldiapp w0,w1,\[x0\],#8'
+.*: Warning: unpredictable transfer with writeback -- `ldiapp w0,w1,\[x1\],#8'
+.*: Warning: unpredictable transfer with writeback -- `ldapr x0,\[x0\],#8'
+.*: Warning: unpredictable transfer with writeback -- `ldapr w0,\[x0\],#4'
+.*: Warning: unpredictable transfer with writeback -- `ldapr x1,\[x1\],#8'
+.*: Warning: unpredictable transfer with writeback -- `ldapr x30,\[x30\],#8'
+.*: Warning: unpredictable transfer with writeback -- `stilp x0,x1,\[x1,#-16\]!'
+.*: Warning: unpredictable transfer with writeback -- `stilp w0,w1,\[x1,#-8\]!'
+.*: Warning: unpredictable transfer with writeback -- `stilp x0,x1,\[x0,#-16\]!'
+.*: Warning: unpredictable transfer with writeback -- `stilp w0,w1,\[x0,#-8\]!'
+.*: Warning: unpredictable transfer with writeback -- `stlr x0,\[x0,#-8\]!'
+.*: Warning: unpredictable transfer with writeback -- `stlr w0,\[x0,#-4\]!'
+.*: Warning: unpredictable transfer with writeback -- `stlr x1,\[x1,#-8\]!'
+.*: Warning: unpredictable transfer with writeback -- `stlr x30,\[x30,#-8\]!'
diff --git a/gas/testsuite/gas/aarch64/rcpc3-fail.s b/gas/testsuite/gas/aarch64/rcpc3-fail.s
index 687bdd7c700..1dfdd979bae 100644
--- a/gas/testsuite/gas/aarch64/rcpc3-fail.s
+++ b/gas/testsuite/gas/aarch64/rcpc3-fail.s
@@ -81,11 +81,6 @@
ldiapp w0, w0, [x1], #8
ldiapp x0, x0, [x1], #16
- stilp w0, w0, [x1]
- stilp x0, x0, [x1]
- stilp w0, w0, [x1, #-8]!
- stilp x0, x0, [x1, #-16]!
-
/* Invalid write back overlap (load)*/
ldiapp x0, x1, [x0], #16
ldiapp x0, x1, [x1], #16
diff --git a/gas/testsuite/gas/aarch64/rcpc3.d b/gas/testsuite/gas/aarch64/rcpc3.d
index 575e46e56ba..36c36a387fb 100644
--- a/gas/testsuite/gas/aarch64/rcpc3.d
+++ b/gas/testsuite/gas/aarch64/rcpc3.d
@@ -28,8 +28,10 @@ Disassembly of section \.text:
[^:]+: 99010860 stilp w0, w1, \[x3, #-8\]!
[^:]+: d9011820 stilp x0, x1, \[x1\]
[^:]+: d9011800 stilp x0, x1, \[x0\]
+[^:]+: d9001800 stilp x0, x0, \[x0\]
[^:]+: 99011820 stilp w0, w1, \[x1\]
[^:]+: 99011800 stilp w0, w1, \[x0\]
+[^:]+: 99001800 stilp w0, w0, \[x0\]
[^:]+: b8bfc020 ldapr w0, \[x1\]
[^:]+: b8bfc020 ldapr w0, \[x1\]
[^:]+: f8bfc020 ldapr x0, \[x1\]
@@ -44,8 +46,10 @@ Disassembly of section \.text:
[^:]+: d9c00be0 ldapr x0, \[sp\], #8
[^:]+: 889ffc20 stlr w0, \[x1\]
[^:]+: 889ffc20 stlr w0, \[x1\]
+[^:]+: 889ffc00 stlr w0, \[x0\]
[^:]+: c89ffc20 stlr x0, \[x1\]
[^:]+: c89ffc20 stlr x0, \[x1\]
+[^:]+: c89ffc00 stlr x0, \[x0\]
[^:]+: 99800841 stlr w1, \[x2, #-4\]!
[^:]+: d9800841 stlr x1, \[x2, #-8\]!
[^:]+: d980081e stlr x30, \[x0, #-8\]!
diff --git a/gas/testsuite/gas/aarch64/rcpc3.s b/gas/testsuite/gas/aarch64/rcpc3.s
index 41026d4ca04..b3e4055e792 100644
--- a/gas/testsuite/gas/aarch64/rcpc3.s
+++ b/gas/testsuite/gas/aarch64/rcpc3.s
@@ -29,8 +29,10 @@
// for store is fine.
stilp x0, x1, [x1]
stilp x0, x1, [x0]
+ stilp x0, x0, [x0]
stilp w0, w1, [x1]
stilp w0, w1, [x0]
+ stilp w0, w0, [x0]
ldapr w0, [x1]
ldapr w0, [x1, #0]
@@ -47,8 +49,10 @@
stlr w0, [x1]
stlr w0, [x1, #0]
+ stlr w0, [x0]
stlr x0, [x1]
stlr x0, [x1, #0]
+ stlr x0, [x0]
stlr w1, [x2, #-4]!
stlr x1, [x2, #-8]!
stlr x30, [x0, #-8]!
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