[PATCH] D146321: [RISCV] Add isReMaterializable to FLI instructions.

[Craig Topper via Phabricator via llvm-commits]

craig.topper created this revision.
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Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D146321

Files:
  llvm/lib/Target/RISCV/RISCVInstrInfoZfa.td
  llvm/test/CodeGen/RISCV/float-zfa.ll


Index: llvm/test/CodeGen/RISCV/float-zfa.ll
===================================================================
--- llvm/test/CodeGen/RISCV/float-zfa.ll
+++ llvm/test/CodeGen/RISCV/float-zfa.ll
@@ -227,3 +227,16 @@
   %2 = zext i1 %1 to i32
   ret i32 %2
 }
+
+declare void @foo(float, float)
+
+; Make sure we use two fli instructions instead of copying.
+define void @fli_remat() {
+; CHECK-LABEL: fli_remat:
+; CHECK:       # %bb.0:
+; CHECK-NEXT:    fli.s fa0, 1.0
+; CHECK-NEXT:    fmv.s fa1, fa0
+; CHECK-NEXT:    tail foo at plt
+  tail call void @foo(float 1.000000e+00, float 1.000000e+00)
+  ret void
+}
Index: llvm/lib/Target/RISCV/RISCVInstrInfoZfa.td
===================================================================
--- llvm/lib/Target/RISCV/RISCVInstrInfoZfa.td
+++ llvm/lib/Target/RISCV/RISCVInstrInfoZfa.td
@@ -93,7 +93,7 @@
 //===----------------------------------------------------------------------===//
 
 let Predicates = [HasStdExtZfa] in {
-let isAsCheapAsAMove = 1 in
+let isReMaterializable = 1, isAsCheapAsAMove = 1 in
 def FLI_S : FPUnaryOp_imm<0b1111000, 0b00001, 0b000, OPC_OP_FP, (outs FPR32:$rd),
             (ins loadfp32imm:$imm), "fli.s", "$rd, $imm">;
 
@@ -108,7 +108,7 @@
 } // Predicates = [HasStdExtZfa]
 
 let Predicates = [HasStdExtZfa, HasStdExtD] in {
-let isAsCheapAsAMove = 1 in
+let isReMaterializable = 1, isAsCheapAsAMove = 1 in
 def FLI_D : FPUnaryOp_imm<0b1111001, 0b00001, 0b000, OPC_OP_FP, (outs FPR64:$rd),
             (ins loadfp64imm:$imm), "fli.d", "$rd, $imm">;
 
@@ -138,7 +138,7 @@
 } // Predicates = [HasStdExtZfa, HasStdExtD, IsRV32]
 
 let Predicates = [HasStdExtZfa, HasStdExtZfhOrZvfh] in
-let isAsCheapAsAMove = 1 in
+let isReMaterializable = 1, isAsCheapAsAMove = 1 in
 def FLI_H : FPUnaryOp_imm<0b1111010, 0b00001, 0b000, OPC_OP_FP, (outs FPR16:$rd),
             (ins loadfp16imm:$imm), "fli.h", "$rd, $imm">;
 


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