[WebAssembly] Rematerialize constants rather than hold them live in registers.

Teach the register stackifier to rematerialize constants that have multiple
uses instead of leaving them in registers. In the WebAssembly encoding, it's
the same code size to materialize most constants as it is to read a value
from a register.

llvm-svn: 258142

1 files changed, 2 insertions, 2 deletions

diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyInstrInfo.td b/llvm/lib/Target/WebAssembly/WebAssemblyInstrInfo.td
index 2e682a47547..75b76565c3f 100644
--- a/llvm/lib/Target/WebAssembly/WebAssemblyInstrInfo.td
+++ b/llvm/lib/Target/WebAssembly/WebAssemblyInstrInfo.td
@@ -123,7 +123,7 @@ defm : LOCAL<I64>;
 defm : LOCAL<F32>;
 defm : LOCAL<F64>;
 
-let isMoveImm = 1 in {
+let isMoveImm = 1, isAsCheapAsAMove = 1, isReMaterializable = 1 in {
 def CONST_I32 : I<(outs I32:$res), (ins i32imm:$imm),
                   [(set I32:$res, imm:$imm)],
                   "i32.const\t$res, $imm">;
@@ -136,7 +136,7 @@ def CONST_F32 : I<(outs F32:$res), (ins f32imm_op:$imm),
 def CONST_F64 : I<(outs F64:$res), (ins f64imm_op:$imm),
                   [(set F64:$res, fpimm:$imm)],
                   "f64.const\t$res, $imm">;
-} // isMoveImm = 1
+} // isMoveImm = 1, isAsCheapAsAMove = 1, isReMaterializable = 1
 
 } // Defs = [ARGUMENTS]