[llvm] r366139 - [WebAssembly] Assembler: support special floats: infinity / nan

[Wouter van Oortmerssen via llvm-commits]

Author: aardappel
Date: Mon Jul 15 15:13:39 2019
New Revision: 366139

URL: http://llvm.org/viewvc/llvm-project?rev=366139&view=rev
Log:
[WebAssembly] Assembler: support special floats: infinity / nan

Summary:
These are emitted as identifiers by the InstPrinter, so we should
parse them as such. These could potentially clash with symbols of
the same name, but that is out of our (the WebAssembly backend) control.

Reviewers: dschuff

Subscribers: sbc100, jgravelle-google, aheejin, sunfish, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D64770

Modified:
    llvm/trunk/lib/Target/WebAssembly/AsmParser/WebAssemblyAsmParser.cpp
    llvm/trunk/test/MC/WebAssembly/basic-assembly.s

Modified: llvm/trunk/lib/Target/WebAssembly/AsmParser/WebAssemblyAsmParser.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/WebAssembly/AsmParser/WebAssemblyAsmParser.cpp?rev=366139&r1=366138&r2=366139&view=diff
==============================================================================
--- llvm/trunk/lib/Target/WebAssembly/AsmParser/WebAssemblyAsmParser.cpp (original)
+++ llvm/trunk/lib/Target/WebAssembly/AsmParser/WebAssemblyAsmParser.cpp Mon Jul 15 15:13:39 2019
@@ -363,6 +363,28 @@ public:
     return false;
   }
 
+  bool parseSpecialFloatMaybe(bool IsNegative, OperandVector &Operands) {
+    if (Lexer.isNot(AsmToken::Identifier))
+      return true;
+    auto &Flt = Lexer.getTok();
+    auto S = Flt.getString();
+    double Val;
+    if (S.compare_lower("infinity") == 0) {
+      Val = std::numeric_limits<double>::infinity();
+    } else if (S.compare_lower("nan") == 0) {
+      Val = std::numeric_limits<double>::quiet_NaN();
+    } else {
+      return true;
+    }
+    if (IsNegative)
+      Val = -Val;
+    Operands.push_back(make_unique<WebAssemblyOperand>(
+        WebAssemblyOperand::Float, Flt.getLoc(), Flt.getEndLoc(),
+        WebAssemblyOperand::FltOp{Val}));
+    Parser.Lex();
+    return false;
+  }
+
   bool checkForP2AlignIfLoadStore(OperandVector &Operands, StringRef InstName) {
     // FIXME: there is probably a cleaner way to do this.
     auto IsLoadStore = InstName.find(".load") != StringRef::npos ||
@@ -476,6 +498,8 @@ public:
       auto &Tok = Lexer.getTok();
       switch (Tok.getKind()) {
       case AsmToken::Identifier: {
+        if (!parseSpecialFloatMaybe(false, Operands))
+          break;
         auto &Id = Lexer.getTok();
         if (ExpectBlockType) {
           // Assume this identifier is a block_type.
@@ -507,6 +531,7 @@ public:
         } else if(Lexer.is(AsmToken::Real)) {
           if (parseSingleFloat(true, Operands))
             return true;
+        } else if (!parseSpecialFloatMaybe(true, Operands)) {
         } else {
           return error("Expected numeric constant instead got: ",
                        Lexer.getTok());

Modified: llvm/trunk/test/MC/WebAssembly/basic-assembly.s
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/MC/WebAssembly/basic-assembly.s?rev=366139&r1=366138&r2=366139&view=diff
==============================================================================
--- llvm/trunk/test/MC/WebAssembly/basic-assembly.s (original)
+++ llvm/trunk/test/MC/WebAssembly/basic-assembly.s Mon Jul 15 15:13:39 2019
@@ -14,6 +14,8 @@ test0:
     i32.const   -1
     f64.const   0x1.999999999999ap1
     f32.const   -1.0
+    f32.const   -infinity
+    f32.const   nan
     v128.const  0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15
     v128.const  0, 1, 2, 3, 4, 5, 6, 7
     # Indirect addressing:
@@ -118,6 +120,8 @@ test0:
 # CHECK-NEXT:      i32.const   -1
 # CHECK-NEXT:      f64.const   0x1.999999999999ap1
 # CHECK-NEXT:      f32.const   -0x1p0
+# CHECK-NEXT:      f32.const   -infinity
+# CHECK-NEXT:      f32.const   nan
 # CHECK-NEXT:      v128.const  0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15
 # CHECK-NEXT:      v128.const  0, 1, 2, 3, 4, 5, 6, 7
 # CHECK-NEXT:      local.get   0