[RISCV] Add RV64F codegen support

This requires a little extra work due tothe fact i32 is not a legal type. When
call lowering happens post-legalisation (e.g. when an intrinsic was inserted
during legalisation). A bitcast from f32 to i32 can't be introduced. This is
similar to the challenges with RV32D. To handle this, we introduce
target-specific DAG nodes that perform bitcast+anyext for f32->i64 and
trunc+bitcast for i64->f32.

Differential Revision: https://reviews.llvm.org/D53235

llvm-svn: 352807

1 files changed, 8 insertions, 1 deletions

diff --git a/llvm/lib/Target/RISCV/RISCVISelLowering.h b/llvm/lib/Target/RISCV/RISCVISelLowering.h
index fa18f7c8e40..12b63208543 100644
--- a/llvm/lib/Target/RISCV/RISCVISelLowering.h
+++ b/llvm/lib/Target/RISCV/RISCVISelLowering.h
@@ -41,7 +41,14 @@ enum NodeType : unsigned {
   // at instruction selection time.
   DIVW,
   DIVUW,
-  REMUW
+  REMUW,
+  // FPR32<->GPR transfer operations for RV64. Needed as an i32<->f32 bitcast
+  // is not legal on RV64. FMV_W_X_RV64 matches the semantics of the FMV.W.X.
+  // FMV_X_ANYEXTW_RV64 is similar to FMV.X.W but has an any-extended result.
+  // This is a more convenient semantic for producing dagcombines that remove
+  // unnecessary GPR->FPR->GPR moves.
+  FMV_W_X_RV64,
+  FMV_X_ANYEXTW_RV64
 };
 }