runtime: use internal/cpu instead of support_avx

After CL 104636 cpu.X86.HasAVX is set early enough that it can be used
to determine useAVXmemmove. Use it and remove support_avx.

Change-Id: Ib7a627bede2bf96c92362507e742bd833cb42a74
Reviewed-on: https://go-review.googlesource.com/106235
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

src/runtime/asm_386.s

@@ -176,11 +176,6 @@ notintel:
 	TESTL	$(1<<27), DI // OSXSAVE
 	SETNE	runtime·support_osxsave(SB)
 
-	// If OS support for XMM and YMM is not present
-	// support_avx will be set back to false later.
-	TESTL	$(1<<28), DI // AVX
-	SETNE	runtime·support_avx(SB)
-
 eax7:
 	// Load EAX=7/ECX=0 cpuid flags
 	CMPL	SI, $7
@@ -211,7 +206,6 @@ osavx:
 	JE nocpuinfo
 #endif
 noavx:
-	MOVB $0, runtime·support_avx(SB)
 	MOVB $0, runtime·support_avx2(SB)
 
 nocpuinfo:

src/runtime/asm_amd64.s

@@ -139,11 +139,6 @@ notintel:
 	TESTL	$(1<<27), CX // OSXSAVE
 	SETNE	runtime·support_osxsave(SB)
 
-	// If OS support for XMM and YMM is not present
-	// support_avx will be set back to false later.
-	TESTL	$(1<<28), CX // AVX
-	SETNE	runtime·support_avx(SB)
-
 eax7:
 	// Load EAX=7/ECX=0 cpuid flags
 	CMPL	SI, $7
@@ -170,7 +165,6 @@ osavx:
 	CMPL	AX, $6 // Check for OS support of XMM and YMM registers.
 	JE nocpuinfo
 noavx:
-	MOVB $0, runtime·support_avx(SB)
 	MOVB $0, runtime·support_avx2(SB)
 
 nocpuinfo:

src/runtime/asm_amd64p32.s

@@ -59,11 +59,6 @@ notintel:
 	TESTL	$(1<<27), CX // OSXSAVE
 	SETNE	runtime·support_osxsave(SB)
 
-	// If OS support for XMM and YMM is not present
-	// support_avx will be set back to false later.
-	TESTL	$(1<<28), CX // AVX
-	SETNE	runtime·support_avx(SB)
-
 eax7:
 	// Load EAX=7/ECX=0 cpuid flags
 	CMPL	SI, $7
@@ -94,7 +89,6 @@ osavx:
 	JE nocpuinfo
 #endif
 noavx:
-	MOVB $0, runtime·support_avx(SB)
 	MOVB $0, runtime·support_avx2(SB)
 
 nocpuinfo:

src/runtime/cpuflags_amd64.go

@@ -4,6 +4,8 @@
 
 package runtime
 
+import "internal/cpu"
+
 var useAVXmemmove bool
 
 func init() {
@@ -16,5 +18,5 @@ func init() {
 		processor == 0x306A0 ||
 		processor == 0x306E0
 
-	useAVXmemmove = support_avx && !isIntelBridgeFamily
+	useAVXmemmove = cpu.X86.HasAVX && !isIntelBridgeFamily
 }

src/runtime/runtime2.go

@@ -771,7 +771,6 @@ var (
 	processorVersionInfo uint32
 	isIntel              bool
 	lfenceBeforeRdtsc    bool
-	support_avx          bool
 	support_avx2         bool
 	support_erms         bool
 	support_osxsave      bool