[llvm] r195679 - Don't use nopl in cpus that don't support it.

[Rafael Espindola]

Author: rafael
Date: Mon Nov 25 14:15:14 2013
New Revision: 195679

URL: http://llvm.org/viewvc/llvm-project?rev=195679&view=rev
Log:
Don't use nopl in cpus that don't support it.

Patch by Mikulas Patocka. I added the test. I checked that for cpu names that
gas knows about, it also doesn't generate nopl.

The modified cpus:
i686 - there are i686-class CPUs that don't have nopl: Via c3, Transmeta
        Crusoe, Microsoft VirtualBox - see
        https://bbs.archlinux.org/viewtopic.php?pid=775414
k6, k6-2, k6-3, winchip-c6, winchip2 - these are 586-class CPUs
via c3 c3-2 - see https://bugs.archlinux.org/task/19733 as a proof that
        Via c3 and c3-Nehemiah don't have nopl

Modified:
    llvm/trunk/lib/Target/X86/MCTargetDesc/X86AsmBackend.cpp
    llvm/trunk/test/MC/X86/x86_nop.s

Modified: llvm/trunk/lib/Target/X86/MCTargetDesc/X86AsmBackend.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/MCTargetDesc/X86AsmBackend.cpp?rev=195679&r1=195678&r2=195679&view=diff
==============================================================================
--- llvm/trunk/lib/Target/X86/MCTargetDesc/X86AsmBackend.cpp (original)
+++ llvm/trunk/lib/Target/X86/MCTargetDesc/X86AsmBackend.cpp Mon Nov 25 14:15:14 2013
@@ -309,8 +309,12 @@ bool X86AsmBackend::writeNopData(uint64_
 
   // This CPU doesnt support long nops. If needed add more.
   // FIXME: Can we get this from the subtarget somehow?
+  // FIXME: We could generated something better than plain 0x90.
   if (CPU == "generic" || CPU == "i386" || CPU == "i486" || CPU == "i586" ||
-      CPU == "pentium" || CPU == "pentium-mmx" || CPU == "geode") {
+      CPU == "pentium" || CPU == "pentium-mmx" || CPU == "i686" ||
+      CPU == "k6" || CPU == "k6-2" || CPU == "k6-3" || CPU == "geode" ||
+      CPU == "winchip-c6" || CPU == "winchip2" || CPU == "c3" ||
+      CPU == "c3-2") {
     for (uint64_t i = 0; i < Count; ++i)
       OW->Write8(0x90);
     return true;

Modified: llvm/trunk/test/MC/X86/x86_nop.s
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/MC/X86/x86_nop.s?rev=195679&r1=195678&r2=195679&view=diff
==============================================================================
--- llvm/trunk/test/MC/X86/x86_nop.s (original)
+++ llvm/trunk/test/MC/X86/x86_nop.s Mon Nov 25 14:15:14 2013
@@ -5,9 +5,32 @@
 # RUN: llvm-mc -filetype=obj -arch=x86 -mcpu=pentium %s | llvm-objdump -d - | FileCheck %s
 # RUN: llvm-mc -filetype=obj -arch=x86 -mcpu=pentium-mmx %s | llvm-objdump -d - | FileCheck %s
 # RUN: llvm-mc -filetype=obj -arch=x86 -mcpu=geode %s | llvm-objdump -d - | FileCheck %s
-# RUN: llvm-mc -filetype=obj -arch=x86 -mcpu=i686 %s | llvm-objdump -d - | not FileCheck %s
+# RUN: llvm-mc -filetype=obj -arch=x86 -mcpu=i686 %s | llvm-objdump -d - | FileCheck %s
+# RUN: llvm-mc -filetype=obj -arch=x86 -mcpu=k6 %s | llvm-objdump -d - | FileCheck %s
+# RUN: llvm-mc -filetype=obj -arch=x86 -mcpu=k6-2 %s | llvm-objdump -d - | FileCheck %s
+# RUN: llvm-mc -filetype=obj -arch=x86 -mcpu=k6-3 %s | llvm-objdump -d - | FileCheck %s
+# RUN: llvm-mc -filetype=obj -arch=x86 -mcpu=winchip-c6 %s | llvm-objdump -d - | FileCheck %s
+# RUN: llvm-mc -filetype=obj -arch=x86 -mcpu=winchip2 %s | llvm-objdump -d - | FileCheck %s
+# RUN: llvm-mc -filetype=obj -arch=x86 -mcpu=c3 %s | llvm-objdump -d - | FileCheck %s
+# RUN: llvm-mc -filetype=obj -arch=x86 -mcpu=c3-2 %s | llvm-objdump -d - | FileCheck %s
+# RUN: llvm-mc -filetype=obj -arch=x86 -mcpu=core2 %s | llvm-objdump -d - | FileCheck --check-prefix=NOPL %s
+
 
-# CHECK-NOT: nop{{[lw]}}
 inc %eax
 .align 8
 inc %eax
+
+// CHECK: 0:	40                                           	incl	%eax
+// CHECK: 1:	90                                           	nop
+// CHECK: 2:	90                                           	nop
+// CHECK: 3:	90                                           	nop
+// CHECK: 4:	90                                           	nop
+// CHECK: 5:	90                                           	nop
+// CHECK: 6:	90                                           	nop
+// CHECK: 7:	90                                           	nop
+// CHECK: 8:	40                                           	incl	%eax
+
+
+// NOPL: 0:	40                                           	incl	%eax
+// NOPL: 1:	0f 1f 80 00 00 00 00                         	nopl	(%eax)
+// NOPL: 8:	40                                           	incl	%eax