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5f36b4cd05
Summary:
According to PTX ISA:
For convenience, ld, st, and cvt instructions permit source and destination data operands to be wider than the instruction-type size, so that narrow values may be loaded, stored, and converted using regular-width registers. For example, 8-bit or 16-bit values may be held directly in 32-bit or 64-bit registers when being loaded, stored, or converted to other types and sizes. The operand type checking rules are relaxed for bit-size and integer (signed and unsigned) instruction types; floating-point instruction types still require that the operand type-size matches exactly, unless the operand is of bit-size type.
So, the ISA does not support load with extending/store with truncatation for floating numbers. This is reflected in setting the loadext/truncstore actions to expand in the code for floating numbers, but vectors of floating numbers are not taken care of.
As a result, loading a vector of floats followed by a fp_extend may be combined by DAGCombiner to a extload, and the extload may be lowered to NVPTXISD::LoadV2 with extending information. However, NVPTXISD::LoadV2 does not perform extending, and no extending instructions are inserted. Finally, PTX instructions with mismatched types are generated, like
ld.v2.f32 {%fd3, %fd4}, [%rd2]
This patch adds the correct actions for vectors of floats, so DAGCombiner would not create loads with extending, and correct code is generated.
Patched by Gang Hu.
Test Plan: Test case attached.
Reviewers: jingyue
Reviewed By: jingyue
Subscribers: llvm-commits, jholewinski
Differential Revision: http://reviews.llvm.org/D10876
llvm-svn: 241191
16 lines
549 B
LLVM
16 lines
549 B
LLVM
; RUN: llc < %s -march=nvptx64 -mcpu=sm_35 | FileCheck %s
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define void @foo(float* nocapture readonly %x_value, double* nocapture %output) #0 {
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%1 = bitcast float* %x_value to <4 x float>*
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%2 = load <4 x float>, <4 x float>* %1, align 16
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%3 = fpext <4 x float> %2 to <4 x double>
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; CHECK-NOT: ld.v2.f32 {%fd{{[0-9]+}}, %fd{{[0-9]+}}}, [%rd{{[0-9]+}}];
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; CHECK: cvt.f64.f32
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; CHECK: cvt.f64.f32
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; CHECK: cvt.f64.f32
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; CHECK: cvt.f64.f32
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%4 = bitcast double* %output to <4 x double>*
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store <4 x double> %3, <4 x double>* %4
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ret void
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}
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