[llvm] [RISCV] add more generic macrofusions (PR #151140)

[Craig Topper via llvm-commits]

================
@@ -91,3 +91,106 @@ def TuneLDADDFusion
                    CheckIsImmOperand<2>,
                    CheckImmOperand<2, 0>
                  ]>>;
+
+// Fuse add with lw:
+//   add rd, rs1, rs2
+//   lw rd, 0(rd)
+def TuneADDLWFusion
+  : SimpleFusion<"add-lw-fusion", "HasADDLWFusion", "Enable ADD+LW macrofusion",
+                 CheckOpcode<[ADD]>,
+                 CheckAll<[
+                   CheckOpcode<[LW]>,
+                   CheckIsImmOperand<2>,
+                   CheckImmOperand<2, 0>
+                 ]>>;
+
+// Fuse add followed by a load (lb, lh, lw, ld, lbu, lhu, lwu):
+//   add rd, rs1, rs2
+//   load rd, 0(rd)
+def TuneADDLoadFusion
+  : SimpleFusion<"add-load-fusion", "HasADDLoadFusion", "Enable ADD + load macrofusion",
+                 CheckOpcode<[ADD]>,
+                 CheckAll<[
+                   CheckOpcode<[LB, LH, LW, LD, LBU, LHU, LWU]>,
+                   CheckIsImmOperand<2>,
+                   CheckImmOperand<2, 0>
+                 ]>>;
+
+// Fuse AUIPC followed by LD:
+//   auipc rd, imm20
+//   ld rd, imm12(rd)
+def TuneAUIPCLDFusion
+  : SimpleFusion<"auipc-ld-fusion", "HasAUIPCLDFusion",
+                 "Enable AUIPC+LD macrofusion",
+                 CheckOpcode<[AUIPC]>,
+                 CheckOpcode<[LD]>>;
+
+// Fuse LUI followed by LD:
+//   lui rd, imm[31:12]
+//   ld rd, imm12(rd)
----------------
topperc wrote:

Does Ventana only support 64-bit loads? That seems limited.

https://github.com/llvm/llvm-project/pull/151140