[SPARC][IAS] Add illtrap alias for unimp

[koachan]

This follows Solaris behavior of allowing both mnemonics all the time.

Fixes #105639.

[llvmbot]

@llvm/pr-subscribers-backend-sparc

Author: Koakuma (koachan)

Changes

This follows GNU and Solaris behavior of allowing both mnemonics all the time.

Fixes #105639.

---

Full diff: https://github.com/llvm/llvm-project/pull/105928.diff

2 Files Affected:

• (modified) llvm/lib/Target/Sparc/SparcInstrAliases.td (+4)
• (modified) llvm/test/MC/Sparc/sparc-misc-instructions.s (+6)

diff --git a/llvm/lib/Target/Sparc/SparcInstrAliases.td b/llvm/lib/Target/Sparc/SparcInstrAliases.td
index e77b7f5c376bf4..722e0463b7bcaa 100644
--- a/llvm/lib/Target/Sparc/SparcInstrAliases.td
+++ b/llvm/lib/Target/Sparc/SparcInstrAliases.td
@@ -601,6 +601,10 @@ def : InstAlias<"flush", (FLUSH), 0>;
 // unimp -> unimp 0
 def : InstAlias<"unimp", (UNIMP 0), 0>;
 
+// Not in spec, but we follow GNU & Solaris behavior of having `illtrap`
+// interchangeable with `unimp` all the time.
+def : MnemonicAlias<"illtrap", "unimp">;
+
 def : MnemonicAlias<"iflush", "flush">;
 
 def : MnemonicAlias<"stub", "stb">;
diff --git a/llvm/test/MC/Sparc/sparc-misc-instructions.s b/llvm/test/MC/Sparc/sparc-misc-instructions.s
index 0547575eb3db51..8119088cd0dbb1 100644
--- a/llvm/test/MC/Sparc/sparc-misc-instructions.s
+++ b/llvm/test/MC/Sparc/sparc-misc-instructions.s
@@ -6,3 +6,9 @@
 
         ! CHECK: unimp 0   ! encoding: [0x00,0x00,0x00,0x00]
         unimp 0
+
+        ! CHECK: unimp 0   ! encoding: [0x00,0x00,0x00,0x00]
+        illtrap
+
+        ! CHECK: unimp 0   ! encoding: [0x00,0x00,0x00,0x00]
+        illtrap 0

[llvmbot]

@llvm/pr-subscribers-mc

Author: Koakuma (koachan)

Changes

This follows GNU and Solaris behavior of allowing both mnemonics all the time.

Fixes #105639.

---

Full diff: https://github.com/llvm/llvm-project/pull/105928.diff

2 Files Affected:

• (modified) llvm/lib/Target/Sparc/SparcInstrAliases.td (+4)
• (modified) llvm/test/MC/Sparc/sparc-misc-instructions.s (+6)

diff --git a/llvm/lib/Target/Sparc/SparcInstrAliases.td b/llvm/lib/Target/Sparc/SparcInstrAliases.td
index e77b7f5c376bf4..722e0463b7bcaa 100644
--- a/llvm/lib/Target/Sparc/SparcInstrAliases.td
+++ b/llvm/lib/Target/Sparc/SparcInstrAliases.td
@@ -601,6 +601,10 @@ def : InstAlias<"flush", (FLUSH), 0>;
 // unimp -> unimp 0
 def : InstAlias<"unimp", (UNIMP 0), 0>;
 
+// Not in spec, but we follow GNU & Solaris behavior of having `illtrap`
+// interchangeable with `unimp` all the time.
+def : MnemonicAlias<"illtrap", "unimp">;
+
 def : MnemonicAlias<"iflush", "flush">;
 
 def : MnemonicAlias<"stub", "stb">;
diff --git a/llvm/test/MC/Sparc/sparc-misc-instructions.s b/llvm/test/MC/Sparc/sparc-misc-instructions.s
index 0547575eb3db51..8119088cd0dbb1 100644
--- a/llvm/test/MC/Sparc/sparc-misc-instructions.s
+++ b/llvm/test/MC/Sparc/sparc-misc-instructions.s
@@ -6,3 +6,9 @@
 
         ! CHECK: unimp 0   ! encoding: [0x00,0x00,0x00,0x00]
         unimp 0
+
+        ! CHECK: unimp 0   ! encoding: [0x00,0x00,0x00,0x00]
+        illtrap
+
+        ! CHECK: unimp 0   ! encoding: [0x00,0x00,0x00,0x00]
+        illtrap 0

[koachan]

CC-ing @alexrp too.

[s-barannikov]

It looks like GNU as doesn't allow it when targeting V8:

test.s: Assembler messages:
test.s:2: Error: Architecture mismatch on "illtrap ".
test.s:2: (Requires v9|v9a|v9b|v9c|v9d|v9e|v9v|v9m|m8; requested architecture is v8.)

[s-barannikov]

https://gcc.godbolt.org/z/q655vcE5x

[koachan]

It looks like GNU as doesn't allow it when targeting V8:

test.s: Assembler messages:
test.s:2: Error: Architecture mismatch on "illtrap ".
test.s:2: (Requires v9|v9a|v9b|v9c|v9d|v9e|v9v|v9m|m8; requested architecture is v8.)

Oh, interesting. Seems like using unimp in V9 is fine but using illtrap in V8 is not.

On the other hand Solaris does allow both mnemonics even when explicitly targeting V8:

$ cat unimp.s
u:
 unimp
 unimp 0
 illtrap
 illtrap 0
 retl
  nop
$ as -m32 -xarch=v8 unimp.s && dis unimp.o
disassembly for unimp.o


section .text
    0x0:                    00 00 00 00  unimp     0x0
    0x4:                    00 00 00 00  unimp     0x0
    0x8:                    00 00 00 00  unimp     0x0
    0xc:                    00 00 00 00  unimp     0x0
    0x10:                   81 c3 e0 08  retl
    0x14:                   01 00 00 00  nop

I'm slightly leaning towards using Solaris behavior in this particular case but in any case either choice is okay by me.

[s-barannikov]

I'm slightly leaning towards using Solaris behavior in this particular case but in any case either choice is okay by me.

I'm not sure we should be looking at the Solaris toolchain at all. llvm-based toolchain isn't a drop-in replacement for it.