[llvm] [RISCV][VLOPT] Add floating point widening and narrowing convert support (PR #122353)

[Michael Maitland via llvm-commits]

https://github.com/michaelmaitland created https://github.com/llvm/llvm-project/pull/122353

We already have getOperandInfo tests that cover this instruction.

>From 56f1065ef80e5dc17d4279b931266fd9d62b8e61 Mon Sep 17 00:00:00 2001
From: Michael Maitland <michaeltmaitland at gmail.com>
Date: Thu, 9 Jan 2025 11:50:50 -0800
Subject: [PATCH] [RISCV][VLOPT] Add floating point widening and narrowing
 convert support

---
 llvm/lib/Target/RISCV/RISCVVLOptimizer.cpp |  8 ++++++--
 llvm/test/CodeGen/RISCV/rvv/vl-opt.mir     | 10 ++++++++++
 2 files changed, 16 insertions(+), 2 deletions(-)

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
+...