[llvm] [RISCV][FPEnv] Lowering of fpenv intrinsics (PR #141498)

[Craig Topper via llvm-commits]

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@@ -0,0 +1,35 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 5
+; RUN: sed 's/iXLen/i32/g' %s | llc -mtriple=riscv32 -mattr=+f -verify-machineinstrs | FileCheck %s
+; RUN: sed 's/iXLen/i64/g' %s | llc -mtriple=riscv64 -mattr=+f -verify-machineinstrs | FileCheck %s
+; RUN: sed 's/iXLen/i32/g' %s | llc -mtriple=riscv32 -mattr=+zfinx -verify-machineinstrs | FileCheck %s
+; RUN: sed 's/iXLen/i64/g' %s | llc -mtriple=riscv64 -mattr=+zfinx -verify-machineinstrs | FileCheck %s
+
+define iXLen @func_get_fpenv() {
+; CHECK-LABEL: func_get_fpenv:
+; CHECK:       # %bb.0: # %entry
+; CHECK-NEXT:    frcsr a0
+; CHECK-NEXT:    ret
+entry:
+  %fpenv = call iXLen @llvm.get.fpenv.iXLen()
+  ret iXLen %fpenv
+}
+
+define void @func_set_fpenv(iXLen %fpenv) {
+; CHECK-LABEL: func_set_fpenv:
+; CHECK:       # %bb.0: # %entry
+; CHECK-NEXT:    fscsr a0
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topperc wrote:

I'm trying to decide how concerned we should be that this generates `fscsr a0, a0` with -O0. The replacement of the destination with `x0` to discard it is treated as an optimization.

https://github.com/llvm/llvm-project/pull/141498