[PowerPC] Support operand modifier 'x' in inline asm

gcc uses operand modifier 'x' in inline asm for VSX registers.
Without this modifier, instructions which use VSX numbering for their
operands are printed as VMX registers. This patch adds support for the
operand modifier 'x'.

Differential Revision: https://reviews.llvm.org/D52244

llvm-svn: 342882
diff --git a/llvm/lib/Target/PowerPC/PPCAsmPrinter.cpp b/llvm/lib/Target/PowerPC/PPCAsmPrinter.cpp
index a9da64c..34c58b2 100644
--- a/llvm/lib/Target/PowerPC/PPCAsmPrinter.cpp
+++ b/llvm/lib/Target/PowerPC/PPCAsmPrinter.cpp
@@ -279,6 +279,21 @@
       if (MI->getOperand(OpNo).isImm())
         O << "i";
       return false;
+    case 'x':
+      if(!MI->getOperand(OpNo).isReg())
+        return true;
+      // This operand uses VSX numbering.
+      // If the operand is a VMX register, convert it to a VSX register.
+      unsigned Reg = MI->getOperand(OpNo).getReg();
+      if (PPCInstrInfo::isVRRegister(Reg))
+        Reg = PPC::VSX32 + (Reg - PPC::V0);
+      else if (PPCInstrInfo::isVFRegister(Reg))
+        Reg = PPC::VSX32 + (Reg - PPC::VF0);
+      const char *RegName;
+      RegName = PPCInstPrinter::getRegisterName(Reg);
+      RegName = stripRegisterPrefix(RegName);
+      O << RegName;
+      return false;
     }
   }
 
diff --git a/llvm/test/CodeGen/PowerPC/inlineasm-vsx-reg.ll b/llvm/test/CodeGen/PowerPC/inlineasm-vsx-reg.ll
new file mode 100644
index 0000000..9de6358
--- /dev/null
+++ b/llvm/test/CodeGen/PowerPC/inlineasm-vsx-reg.ll
@@ -0,0 +1,22 @@
+; RUN: llc -verify-machineinstrs -ppc-vsr-nums-as-vr -ppc-asm-full-reg-names  -mcpu=pwr9 -mtriple=powerpc64le-unknown-unknown < %s | FileCheck %s
+define signext i32 @foo(<4 x float> %__A) {
+entry:
+  %0 = tail call { i32, <4 x float> } asm "xxsldwi ${1:x},${2:x},${2:x},3;\0Axscvspdp ${1:x},${1:x};\0Afctiw  $1,$1;\0Amfvsrd  $0,${1:x};\0A", "=r,=&^wa,^wa"(<4 x float> %__A)
+  %asmresult = extractvalue { i32, <4 x float> } %0, 0
+  ret i32 %asmresult
+; CHECK: #APP
+; CHECK: xxsldwi vs0, v2, v2, 3
+; CHECK: xscvspdp f0, f0
+; CHECK: fctiw f0, f0
+; CHECK: mffprd r3, f0
+; CHECK: #NO_APP
+}
+
+define double @test() {
+  entry:
+    %0 = tail call double asm "mtvsrd ${0:x}, 1", "=^ws,~{f0},~{f1},~{f2},~{f3},~{f4},~{f5},~{f6},~{f7},~{f8},~{f9},~{f10},~{f11},~{f12},~{f13},~{f14}"()
+    ret double %0
+; CHECK: #APP
+; CHECK: mtvsrd v2, r1
+; CHECK: #NO_APP
+}