llvm/test/CodeGen/X86/rdpmc.ll
Andrea Di Biagio e6cfdc8471 [X86] Add support for builtin to read performance monitoring counters.
This patch adds support for a new builtin instruction called
__builtin_ia32_rdpmc.

Builtin '__builtin_ia32_rdpmc' is defined as a 'GCC builtin'; on X86, it can
be used to read performance monitoring counters. It takes as input the index
of the performance counter to read, and returns the value of the specified
performance counter as a 64-bit number.

Calls to this new builtin will map to instruction RDPMC.
The index in input to the builtin call is moved to register %ECX. The result
of the builtin call is the value of the specified performance counter (RDPMC
would return that quantity in registers RDX:RAX).

This patch:
 - Adds builtin int_x86_rdpmc as a GCCBuiltin;
 - Adds a new x86 DAG node called 'RDPMC_DAG';
 - Teaches how to lower this new builtin;
 - Adds an ISel pattern to select instruction RDPMC;
 - Fixes the definition of instruction RDPMC adding %RAX and %RDX as
   implicit definitions, and adding %ECX as implicit use;
 - Adds a LLVM test to verify that the new builtin is correctly selected.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@212049 91177308-0d34-0410-b5e6-96231b3b80d8
2014-06-30 17:14:21 +00:00

23 lines
577 B
LLVM

; RUN: llc < %s -march=x86-64 -mcpu=generic | FileCheck %s --check-prefix=CHECK --check-prefix=X86-64
; RUN: llc < %s -march=x86 -mcpu=generic | FileCheck %s --check-prefix=CHECK --check-prefix=X86
; Verify that we correctly lower the "Read Performance-Monitoring Counters"
; x86 builtin.
define i64 @test_builtin_read_pmc(i32 %ID) {
%1 = tail call i64 @llvm.x86.rdpmc(i32 %ID)
ret i64 %1
}
; CHECK-LABEL: test_builtin_read_pmc
; CHECK: rdpmc
; X86-NOT: shlq
; X86-NOT: or
; X86-64: shlq
; X86-64: or
; CHECK-NOT: mov
; CHECK: ret
declare i64 @llvm.x86.rdpmc(i32 %ID)