[RISCV][VLOPT] Add floating point widening and narrowing bf16 convert support

[michaelmaitland]

We already have getOperandInfo tests that cover this instruction.

[llvmbot]

@llvm/pr-subscribers-backend-risc-v

Author: Michael Maitland (michaelmaitland)

Changes

We already have getOperandInfo tests that cover this instruction.

---

Full diff: https://github.com/llvm/llvm-project/pull/122353.diff

2 Files Affected:

• (modified) llvm/lib/Target/RISCV/RISCVVLOptimizer.cpp (+6-2)
• (modified) llvm/test/CodeGen/RISCV/rvv/vl-opt.mir (+10)

diff --git a/llvm/lib/Target/RISCV/RISCVVLOptimizer.cpp b/llvm/lib/Target/RISCV/RISCVVLOptimizer.cpp
index 6661921d66f95e..db18ee2ac6e050 100644
--- a/llvm/lib/Target/RISCV/RISCVVLOptimizer.cpp
+++ b/llvm/lib/Target/RISCV/RISCVVLOptimizer.cpp
@@ -550,7 +550,8 @@ getOperandLog2EEW(const MachineOperand &MO, const MachineRegisterInfo *MRI) {
   case RISCV::VFWCVT_RTZ_X_F_V:
   case RISCV::VFWCVT_F_XU_V:
   case RISCV::VFWCVT_F_X_V:
-  case RISCV::VFWCVT_F_F_V: {
+  case RISCV::VFWCVT_F_F_V:
+  case RISCV::VFWCVTBF16_F_F_V: {
     unsigned Log2EEW = IsMODef ? MILog2SEW + 1 : MILog2SEW;
     return Log2EEW;
   }
@@ -610,7 +611,8 @@ getOperandLog2EEW(const MachineOperand &MO, const MachineRegisterInfo *MRI) {
   case RISCV::VFNCVT_F_XU_W:
   case RISCV::VFNCVT_F_X_W:
   case RISCV::VFNCVT_F_F_W:
-  case RISCV::VFNCVT_ROD_F_F_W: {
+  case RISCV::VFNCVT_ROD_F_F_W:
+  case RISCV::VFNCVTBF16_F_F_W: {
     bool IsOp1 = HasPassthru ? MO.getOperandNo() == 2 : MO.getOperandNo() == 1;
     bool TwoTimes = IsOp1;
     unsigned Log2EEW = TwoTimes ? MILog2SEW + 1 : MILog2SEW;
@@ -1033,6 +1035,7 @@ static bool isSupportedInstr(const MachineInstr &MI) {
   case RISCV::VFWCVT_F_XU_V:
   case RISCV::VFWCVT_F_X_V:
   case RISCV::VFWCVT_F_F_V:
+  case RISCV::VFWCVTBF16_F_F_V:
   // Narrowing Floating-Point/Integer Type-Convert Instructions
   case RISCV::VFNCVT_XU_F_W:
   case RISCV::VFNCVT_X_F_W:
@@ -1042,6 +1045,7 @@ static bool isSupportedInstr(const MachineInstr &MI) {
   case RISCV::VFNCVT_F_X_W:
   case RISCV::VFNCVT_F_F_W:
   case RISCV::VFNCVT_ROD_F_F_W:
+  case RISCV::VFNCVTBF16_F_F_W:
     return true;
   }
 
diff --git a/llvm/test/CodeGen/RISCV/rvv/vl-opt.mir b/llvm/test/CodeGen/RISCV/rvv/vl-opt.mir
index 0a366f4fd89cfa..8144610f054c0a 100644
--- a/llvm/test/CodeGen/RISCV/rvv/vl-opt.mir
+++ b/llvm/test/CodeGen/RISCV/rvv/vl-opt.mir
@@ -130,4 +130,14 @@ body: |
     %x:vr = PseudoVFCVT_X_F_V_M1 $noreg, $noreg, 0, -1, 3 /* e32 */, 0
     %y:vr = PseudoVADD_VV_M1 $noreg, %x, $noreg, 1, 3 /* e8 */, 0
 ...
+---
+name: vfcvtbf16_x_f_v_nofpexcept
+body: |
+  bb.0:
+    ; CHECK-LABEL: name: vfcvt_x_f_v_nofpexcept
+    ; CHECK: %x:vr = nofpexcept PseudoVFCVT_X_F_V_M1 $noreg, $noreg, 0, 1, 3 /* e8 */, 0 /* tu, mu */
+    ; CHECK-NEXT: %y:vr = PseudoVADD_VV_M1 $noreg, %x, $noreg, 1, 3 /* e8 */, 0 /* tu, mu */
+    %x:vr = nofpexcept PseudoVFCVT_X_F_V_M1 $noreg, $noreg, 0, -1, 4 /* e16 */, 0
+    %y:vr = PseudoVADD_VV_M1 $noreg, %x, $noreg, 1, 4 /* e16 */, 0
+...
 

[preames]

LGTM - but please change the submit title to make it clear this is only the bf16 converts. As written the description sounds much more generic.

[lukel97]

LGTM w/ title updated to mention bf16

[topperc]

LGTM