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llvm-mirror/test/CodeGen/RISCV/float-isnan.ll
Sam Elliott ea67f31d92 [RISCV] Add patterns for checking isnan
Summary:
This patch addresses some weird assembly sequences we were seeing during
comparing floats. In particular, comparing a float to itself tells you whether
it is NaN or not, which we were doing correctly, but with an extra unneeded
`and` instruction.

This patch specialises the existing patterns to remove the `and` instructions
when both their operands are the same.

Reviewed By: luismarques, asb

Differential Revision: https://reviews.llvm.org/D78908
2020-05-02 15:01:04 +01:00

36 lines
1.1 KiB
LLVM

; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
; RUN: llc -mtriple=riscv32 -mattr=+f -target-abi ilp32f -verify-machineinstrs \
; RUN: < %s | FileCheck -check-prefix=RV32IF %s
; RUN: llc -mtriple=riscv64 -mattr=+f -target-abi lp64f -verify-machineinstrs \
; RUN: < %s | FileCheck -check-prefix=RV64IF %s
define zeroext i1 @float_is_nan(float %a) nounwind {
; RV32IF-LABEL: float_is_nan:
; RV32IF: # %bb.0:
; RV32IF-NEXT: feq.s a0, fa0, fa0
; RV32IF-NEXT: seqz a0, a0
; RV32IF-NEXT: ret
;
; RV64IF-LABEL: float_is_nan:
; RV64IF: # %bb.0:
; RV64IF-NEXT: feq.s a0, fa0, fa0
; RV64IF-NEXT: seqz a0, a0
; RV64IF-NEXT: ret
%1 = fcmp uno float %a, 0.000000e+00
ret i1 %1
}
define zeroext i1 @float_not_nan(float %a) nounwind {
; RV32IF-LABEL: float_not_nan:
; RV32IF: # %bb.0:
; RV32IF-NEXT: feq.s a0, fa0, fa0
; RV32IF-NEXT: ret
;
; RV64IF-LABEL: float_not_nan:
; RV64IF: # %bb.0:
; RV64IF-NEXT: feq.s a0, fa0, fa0
; RV64IF-NEXT: ret
%1 = fcmp ord float %a, 0.000000e+00
ret i1 %1
}