c2e84072bd
`-riscv-fp-imm-cost` controls the threshold at which the constant pool is used for float constants rather than generating directly (typically into a GPR followed by an `fmv`). The value used for this knob indicates the number of instructions that can be used to produce the value (otherwise we fall back to the constant pool). Upping to to 3 covers a huge number of additional constants (see <https://github.com/llvm/llvm-project/issues/153402>), e.g. most whole numbers which can be generated through lui+shift+fmv. As in general we struggle with efficient code generation for constant pool accesses, reducing the number of constant pool accesses is beneficial. We are typically replacing a two-instruction sequence (which includes a load) with a three instruction sequence (two simple arithmetic operations plus a fmv), which. The CHECK prefixes for various tests had to be updated to avoid conflicts leading to check lines being dropped altogether (see <https://github.com/llvm/llvm-project/pull/159321> for a change to update_llc_test_checks to aid diagnosing this).
75 lines
2.3 KiB
LLVM
75 lines
2.3 KiB
LLVM
; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
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; RUN: llc -mtriple=riscv32 -mattr=+f -verify-machineinstrs < %s \
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; RUN: -target-abi=ilp32f | FileCheck %s
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; RUN: llc -mtriple=riscv64 -mattr=+f -verify-machineinstrs < %s \
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; RUN: -target-abi=lp64f | FileCheck %s
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; RUN: llc -mtriple=riscv32 -mattr=+zfinx -verify-machineinstrs < %s \
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; RUN: -target-abi=ilp32 | FileCheck --check-prefixes=CHECKZFINX,RV32ZFINX %s
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; RUN: llc -mtriple=riscv64 -mattr=+zfinx -verify-machineinstrs < %s \
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; RUN: -target-abi=lp64 | FileCheck --check-prefixes=CHECKZFINX,RV64ZFINX %s
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; TODO: constant pool shouldn't be necessary for RV64IF.
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define float @float_imm() nounwind {
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; CHECK-LABEL: float_imm:
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; CHECK: # %bb.0:
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; CHECK-NEXT: lui a0, 263313
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; CHECK-NEXT: addi a0, a0, -37
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; CHECK-NEXT: fmv.w.x fa0, a0
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; CHECK-NEXT: ret
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;
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; CHECKZFINX-LABEL: float_imm:
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; CHECKZFINX: # %bb.0:
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; CHECKZFINX-NEXT: lui a0, 263313
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; CHECKZFINX-NEXT: addi a0, a0, -37
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; CHECKZFINX-NEXT: # kill: def $x10_w killed $x10_w killed $x10
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; CHECKZFINX-NEXT: ret
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ret float 3.14159274101257324218750
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}
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define float @float_imm_op(float %a) nounwind {
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; CHECK-LABEL: float_imm_op:
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; CHECK: # %bb.0:
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; CHECK-NEXT: lui a0, 260096
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; CHECK-NEXT: fmv.w.x fa5, a0
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; CHECK-NEXT: fadd.s fa0, fa0, fa5
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; CHECK-NEXT: ret
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;
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; CHECKZFINX-LABEL: float_imm_op:
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; CHECKZFINX: # %bb.0:
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; CHECKZFINX-NEXT: lui a1, 260096
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; CHECKZFINX-NEXT: fadd.s a0, a0, a1
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; CHECKZFINX-NEXT: ret
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%1 = fadd float %a, 1.0
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ret float %1
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}
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define float @float_positive_zero(ptr %pf) nounwind {
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; CHECK-LABEL: float_positive_zero:
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; CHECK: # %bb.0:
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; CHECK-NEXT: fmv.w.x fa0, zero
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; CHECK-NEXT: ret
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;
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; CHECKZFINX-LABEL: float_positive_zero:
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; CHECKZFINX: # %bb.0:
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; CHECKZFINX-NEXT: li a0, 0
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; CHECKZFINX-NEXT: ret
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ret float 0.0
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}
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define float @float_negative_zero(ptr %pf) nounwind {
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; CHECK-LABEL: float_negative_zero:
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; CHECK: # %bb.0:
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; CHECK-NEXT: lui a0, 524288
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; CHECK-NEXT: fmv.w.x fa0, a0
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; CHECK-NEXT: ret
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;
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; CHECKZFINX-LABEL: float_negative_zero:
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; CHECKZFINX: # %bb.0:
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; CHECKZFINX-NEXT: lui a0, 524288
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; CHECKZFINX-NEXT: ret
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ret float -0.0
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}
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;; NOTE: These prefixes are unused and the list is autogenerated. Do not add tests below this line:
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; RV32ZFINX: {{.*}}
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; RV64ZFINX: {{.*}}
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