[llvm] r253905 - [WebAssembly] Don't use set_local instructions explicitly.

[Dan Gohman via llvm-commits]

Author: djg
Date: Mon Nov 23 13:30:43 2015
New Revision: 253905

URL: http://llvm.org/viewvc/llvm-project?rev=253905&view=rev
Log:
[WebAssembly] Don't use set_local instructions explicitly.

The current approach to using get_local and set_local is to use them
implicitly, as register uses and defs. Introduce new copy instructions
which are themselves no-ops except for the get_local and set_local
that they imply, so that we use get_local and set_local consistently.

Modified:
    llvm/trunk/lib/Target/WebAssembly/WebAssemblyInstrInfo.cpp
    llvm/trunk/lib/Target/WebAssembly/WebAssemblyInstrInfo.td
    llvm/trunk/test/CodeGen/WebAssembly/phi.ll

Modified: llvm/trunk/lib/Target/WebAssembly/WebAssemblyInstrInfo.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/WebAssembly/WebAssemblyInstrInfo.cpp?rev=253905&r1=253904&r2=253905&view=diff
==============================================================================
--- llvm/trunk/lib/Target/WebAssembly/WebAssemblyInstrInfo.cpp (original)
+++ llvm/trunk/lib/Target/WebAssembly/WebAssemblyInstrInfo.cpp Mon Nov 23 13:30:43 2015
@@ -37,19 +37,19 @@ void WebAssemblyInstrInfo::copyPhysReg(M
   const TargetRegisterClass *RC =
       MBB.getParent()->getRegInfo().getRegClass(SrcReg);
 
-  unsigned SetLocalOpcode;
+  unsigned CopyLocalOpcode;
   if (RC == &WebAssembly::I32RegClass)
-    SetLocalOpcode = WebAssembly::SET_LOCAL_I32;
+    CopyLocalOpcode = WebAssembly::COPY_LOCAL_I32;
   else if (RC == &WebAssembly::I64RegClass)
-    SetLocalOpcode = WebAssembly::SET_LOCAL_I64;
+    CopyLocalOpcode = WebAssembly::COPY_LOCAL_I64;
   else if (RC == &WebAssembly::F32RegClass)
-    SetLocalOpcode = WebAssembly::SET_LOCAL_F32;
+    CopyLocalOpcode = WebAssembly::COPY_LOCAL_F32;
   else if (RC == &WebAssembly::F64RegClass)
-    SetLocalOpcode = WebAssembly::SET_LOCAL_F64;
+    CopyLocalOpcode = WebAssembly::COPY_LOCAL_F64;
   else
     llvm_unreachable("Unexpected register class");
 
-  BuildMI(MBB, I, DL, get(SetLocalOpcode), DestReg)
+  BuildMI(MBB, I, DL, get(CopyLocalOpcode), DestReg)
       .addReg(SrcReg, KillSrc ? RegState::Kill : 0);
 }
 

Modified: llvm/trunk/lib/Target/WebAssembly/WebAssemblyInstrInfo.td
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/WebAssembly/WebAssemblyInstrInfo.td?rev=253905&r1=253904&r2=253905&view=diff
==============================================================================
--- llvm/trunk/lib/Target/WebAssembly/WebAssemblyInstrInfo.td (original)
+++ llvm/trunk/lib/Target/WebAssembly/WebAssemblyInstrInfo.td Mon Nov 23 13:30:43 2015
@@ -98,6 +98,14 @@ multiclass LOCAL<WebAssemblyRegClass vt>
   // TODO: set_local returns its operand value
   def SET_LOCAL_#vt : I<(outs), (ins i32imm:$regno, vt:$src), [],
                         "set_local\t$regno, $src">;
+
+  // COPY_LOCAL is not an actual instruction in wasm, but since we allow
+  // get_local and set_local to be implicit, we can have a COPY_LOCAL which
+  // is actually a no-op because all the work is done in the implied
+  // get_local and set_local.
+  let isAsCheapAsAMove = 1 in
+  def COPY_LOCAL_#vt : I<(outs vt:$res), (ins vt:$src), [],
+                         "copy_local\t$res, $src">;
 }
 defm : LOCAL<I32>;
 defm : LOCAL<I64>;

Modified: llvm/trunk/test/CodeGen/WebAssembly/phi.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/WebAssembly/phi.ll?rev=253905&r1=253904&r2=253905&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/WebAssembly/phi.ll (original)
+++ llvm/trunk/test/CodeGen/WebAssembly/phi.ll Mon Nov 23 13:30:43 2015
@@ -26,9 +26,9 @@ done:
 
 ; CHECK-LABEL: test1:
 ; CHECK: BB1_1:
-; CHECK: set_local $[[NUM0:[0-9]+]], $[[NUM1:[0-9]+]]{{$}}
-; CHECK: set_local $[[NUM1]], $[[NUM2:[0-9]+]]{{$}}
-; CHECK: set_local $[[NUM2]], $[[NUM0]]{{$}}
+; CHECK: copy_local $[[NUM0:[0-9]+]], $[[NUM1:[0-9]+]]{{$}}
+; CHECK: copy_local $[[NUM1]], $[[NUM2:[0-9]+]]{{$}}
+; CHECK: copy_local $[[NUM2]], $[[NUM0]]{{$}}
 define i32 @test1(i32 %n) {
 entry:
   br label %loop