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llvm-mirror/test/CodeGen/NVPTX/proxy-reg-erasure-mir.ll
Justin Lebar 10af09a34f [NVPTX] Allow libcalls that are defined in the current module.
The patch adds a possibility to make library calls on NVPTX.

An important thing about library functions - they must be defined within
the current module. This basically should guarantee that we produce a
valid PTX assembly (without calls to not defined functions). The one who
wants to use the libcalls is probably will have to link against
compiler-rt or any other implementation.

Currently, it's completely impossible to make library calls because of
error LLVM ERROR: Cannot select: i32 = ExternalSymbol '...'. But we can
lower ExternalSymbol to TargetExternalSymbol and verify if the function
definition is available.

Also, there was an issue with a DAG during legalisation. When we expand
instruction into libcall, the inner call-chain isn't being "integrated"
into outer chain. Since the last "data-flow" (call retval load) node is
located in call-chain earlier than CALLSEQ_END node, the latter becomes
a leaf and therefore a dead node (and is being removed quite fast).
Proposed here solution relies on another data-flow pseudo nodes
(ProxyReg) which purpose is only to keep CALLSEQ_END at legalisation and
instruction selection phases - we remove the pseudo instructions before
register scheduling phase.

Patch by Denys Zariaiev!

Differential Revision: https://reviews.llvm.org/D34708

llvm-svn: 350069
2018-12-26 19:12:31 +00:00

26 lines
1.0 KiB
LLVM

; RUN: llc -march=nvptx64 -stop-before=nvptx-proxyreg-erasure < %s 2>&1 \
; RUN: | FileCheck %s --check-prefix=MIR --check-prefix=MIR-BEFORE
; RUN: llc -march=nvptx64 -stop-after=nvptx-proxyreg-erasure < %s 2>&1 \
; RUN: | FileCheck %s --check-prefix=MIR --check-prefix=MIR-AFTER
; Check ProxyRegErasure pass MIR manipulation.
declare <4 x i32> @callee_vec_i32()
define <4 x i32> @check_vec_i32() {
; MIR: body:
; MIR-DAG: Callseq_Start {{[0-9]+}}, {{[0-9]+}}
; MIR-DAG: %0:int32regs, %1:int32regs, %2:int32regs, %3:int32regs = LoadParamMemV4I32 0
; MIR-DAG: Callseq_End {{[0-9]+}}
; MIR-BEFORE-DAG: %4:int32regs = ProxyRegI32 killed %0
; MIR-BEFORE-DAG: %5:int32regs = ProxyRegI32 killed %1
; MIR-BEFORE-DAG: %6:int32regs = ProxyRegI32 killed %2
; MIR-BEFORE-DAG: %7:int32regs = ProxyRegI32 killed %3
; MIR-BEFORE-DAG: StoreRetvalV4I32 killed %4, killed %5, killed %6, killed %7, 0
; MIR-AFTER-DAG: StoreRetvalV4I32 killed %0, killed %1, killed %2, killed %3, 0
%ret = call <4 x i32> @callee_vec_i32()
ret <4 x i32> %ret
}