Add a Subtarget feature 'v8fp' to the ARM backend.

llvm-svn: 185073

llvm/docs/CompilerWriterInfo.rst

@@ -20,6 +20,8 @@ ARM
 
 * `ABI <http://www.arm.com/products/DevTools/ABI.html>`_
 
+* `ABI Addenda and Errata <http://infocenter.arm.com/help/topic/com.arm.doc.ihi0045d/IHI0045D_ABI_addenda.pdf>`_
+
 * `ARM C Language Extensions <http://infocenter.arm.com/help/topic/com.arm.doc.ihi0053a/IHI0053A_acle.pdf>`_
 
 AArch64

llvm/lib/Target/ARM/ARM.td

@@ -45,6 +45,9 @@ def FeatureFP16   : SubtargetFeature<"fp16", "HasFP16", "true",
 def FeatureVFP4   : SubtargetFeature<"vfp4", "HasVFPv4", "true",
                                      "Enable VFP4 instructions",
                                      [FeatureVFP3, FeatureFP16]>;
+def FeatureV8FP : SubtargetFeature<"v8fp", "HasV8FP",
+                                   "true", "Enable ARMv8 FP",
+                                   [FeatureVFP4]>;
 def FeatureD16    : SubtargetFeature<"d16", "HasD16", "true",
                                      "Restrict VFP3 to 16 double registers">;
 def FeatureHWDiv  : SubtargetFeature<"hwdiv", "HasHardwareDivide", "true",

llvm/lib/Target/ARM/ARMAsmPrinter.cpp

@@ -781,8 +781,14 @@ void ARMAsmPrinter::emitAttributes() {
     emitFPU = false;
   }
 
-  /* VFPv4 + .fpu */
-  if (Subtarget->hasVFP4()) {
+  /* V8FP + .fpu */
+  if (Subtarget->hasV8FP()) {
+    AttrEmitter->EmitAttribute(ARMBuildAttrs::VFP_arch,
+                               ARMBuildAttrs::AllowV8FPA);
+    if (emitFPU)
+      AttrEmitter->EmitTextAttribute(ARMBuildAttrs::VFP_arch, "v8fp");
+    /* VFPv4 + .fpu */
+  } else if (Subtarget->hasVFP4()) {
     AttrEmitter->EmitAttribute(ARMBuildAttrs::VFP_arch,
                                ARMBuildAttrs::AllowFPv4A);
     if (emitFPU)
@@ -806,8 +812,12 @@ void ARMAsmPrinter::emitAttributes() {
   /* TODO: ARMBuildAttrs::Allowed is not completely accurate,
    * since NEON can have 1 (allowed) or 2 (MAC operations) */
   if (Subtarget->hasNEON()) {
-    AttrEmitter->EmitAttribute(ARMBuildAttrs::Advanced_SIMD_arch,
-                               ARMBuildAttrs::Allowed);
+    if (Subtarget->hasV8Ops())
+      AttrEmitter->EmitAttribute(ARMBuildAttrs::Advanced_SIMD_arch,
+                                 ARMBuildAttrs::AllowedNeonV8);
+    else
+      AttrEmitter->EmitAttribute(ARMBuildAttrs::Advanced_SIMD_arch,
+                                 ARMBuildAttrs::Allowed);
   }
 
   // Signal various FP modes.

llvm/lib/Target/ARM/ARMBuildAttrs.h

@@ -106,6 +106,7 @@ namespace ARMBuildAttrs {
     //ARMISAUse (=8), uleb128  and THUMBISAUse (=9), uleb128
     Not_Allowed = 0,
     Allowed = 1,
+    AllowedNeonV8 = 3,
 
     // FP_arch (=10), uleb128 (formerly Tag_VFP_arch = 10)
     AllowFPv2  = 2, // v2 FP ISA permitted (implies use of the v1 FP ISA)
@@ -113,6 +114,8 @@ namespace ARMBuildAttrs {
     AllowFPv3B = 4, // v3 FP ISA permitted, but only D0-D15, S0-S31 
     AllowFPv4A = 5, // v4 FP ISA permitted (implies use of v3 FP ISA) 
     AllowFPv4B = 6, // v4 FP ISA was permitted, but only D0-D15, S0-S31
+    AllowV8FPA = 7, // Use of the ARM v8-A FP ISA was permitted
+    AllowV8FPB = 8, // Use of the ARM v8-A FP ISA was permitted, but only D0-D15, S0-S31
 
     // Tag_WMMX_arch, (=11), uleb128
     AllowThumb32 = 2, // 32-bit Thumb (implies 16-bit instructions)

llvm/lib/Target/ARM/ARMSubtarget.cpp

@@ -81,6 +81,7 @@ void ARMSubtarget::initializeEnvironment() {
   HasVFPv2 = false;
   HasVFPv3 = false;
   HasVFPv4 = false;
+  HasV8FP = false;
   HasNEON = false;
   UseNEONForSinglePrecisionFP = false;
   UseMulOps = UseFusedMulOps;

llvm/lib/Target/ARM/ARMSubtarget.h

@@ -48,11 +48,12 @@ protected:
   bool HasV7Ops;
   bool HasV8Ops;
 
-  /// HasVFPv2, HasVFPv3, HasVFPv4, HasNEON - Specify what
+  /// HasVFPv2, HasVFPv3, HasVFPv4, HasV8FP, HasNEON - Specify what
   /// floating point ISAs are supported.
   bool HasVFPv2;
   bool HasVFPv3;
   bool HasVFPv4;
+  bool HasV8FP;
   bool HasNEON;
 
   /// UseNEONForSinglePrecisionFP - if the NEONFP attribute has been
@@ -249,6 +250,7 @@ public:
   bool hasVFP2() const { return HasVFPv2; }
   bool hasVFP3() const { return HasVFPv3; }
   bool hasVFP4() const { return HasVFPv4; }
+  bool hasV8FP() const { return HasV8FP; }
   bool hasNEON() const { return HasNEON;  }
   bool useNEONForSinglePrecisionFP() const {
     return hasNEON() && UseNEONForSinglePrecisionFP; }

llvm/test/CodeGen/ARM/2010-09-29-mc-asm-header-test.ll

@@ -1,6 +1,8 @@
 ; RUN: llc < %s -mtriple=armv7-linux-gnueabi | FileCheck %s --check-prefix=V7
 ; RUN: llc < %s -mtriple=armv8-linux-gnueabi | FileCheck %s --check-prefix=V8
 ; RUN: llc < %s -mtriple=thumbv8-linux-gnueabi | FileCheck %s --check-prefix=Vt8
+; RUN: llc < %s -mtriple=armv8-linux-gnueabi -mattr=+v8fp | FileCheck %s --check-prefix=V8-V8FP
+; RUN: llc < %s -mtriple=armv8-linux-gnueabi -mattr=+neon | FileCheck %s --check-prefix=V8-NEON
 ; This tests that MC/asm header conversion is smooth
 ;
 ; V7:      .syntax unified
@@ -17,6 +19,14 @@
 ; Vt8:     .syntax unified
 ; Vt8: .eabi_attribute 6, 14
 
+; V8-V8FP:      .syntax unified
+; V8-V8FP: .eabi_attribute 6, 14
+; V8-V8FP: .eabi_attribute 10, 7
+
+; V8-NEON:      .syntax unified
+; V8-NEON: .eabi_attribute 6, 14
+; V8-NEON: .eabi_attribute 12, 3
+
 define i32 @f(i64 %z) {
 	ret i32 0
 }