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).
33 lines
1.2 KiB
LLVM
33 lines
1.2 KiB
LLVM
; RUN: sed 's/SMALL_DATA_LIMIT/0/g' %s | \
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; RUN: llc -mtriple=riscv32 -mattr=+d | \
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; RUN: FileCheck -check-prefix=CHECK-SDL-0 %s
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; RUN: sed 's/SMALL_DATA_LIMIT/0/g' %s | \
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; RUN: llc -mtriple=riscv64 -mattr=+d | \
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; RUN: FileCheck -check-prefix=CHECK-SDL-0 %s
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; RUN: sed 's/SMALL_DATA_LIMIT/8/g' %s | \
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; RUN: llc -mtriple=riscv32 -mattr=+d | \
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; RUN: FileCheck -check-prefix=CHECK-SDL-8 %s
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; RUN: sed 's/SMALL_DATA_LIMIT/8/g' %s | \
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; RUN: llc -mtriple=riscv64 -mattr=+d | \
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; RUN: FileCheck -check-prefix=CHECK-SDL-8 %s
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; RUN: sed 's/SMALL_DATA_LIMIT/16/g' %s | \
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; RUN: llc -mtriple=riscv32 -mattr=+d | \
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; RUN: FileCheck -check-prefix=CHECK-SDL-16 %s
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; RUN: sed 's/SMALL_DATA_LIMIT/16/g' %s | \
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; RUN: llc -mtriple=riscv64 -mattr=+d | \
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; RUN: FileCheck -check-prefix=CHECK-SDL-16 %s
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define dso_local double @foo() {
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entry:
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ret double 0x400A08AC91C3E242
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}
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!llvm.module.flags = !{!0}
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!0 = !{i32 8, !"SmallDataLimit", i32 SMALL_DATA_LIMIT}
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; CHECK-SDL-0-NOT: .section .srodata.cst4
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; CHECK-SDL-0-NOT: .section .srodata.cst8
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; CHECK-SDL-8: .section .srodata.cst8
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; CHECK-SDL-16: .section .srodata.cst8
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