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llvm-mirror/test/CodeGen/AArch64/directcond.ll
Tim Northover 3bb84c9bcc ARM & AArch64: make use of common cmpxchg idioms after expansion
The C and C++ semantics for compare_exchange require it to return a bool
indicating success. This gets mapped to LLVM IR which follows each cmpxchg with
an icmp of the value loaded against the desired value.

When lowered to ldxr/stxr loops, this extra comparison is redundant: its
results are implicit in the control-flow of the function.

This commit makes two changes: it replaces that icmp with appropriate PHI
nodes, and then makes sure earlyCSE is called after expansion to actually make
use of the opportunities revealed.

I've also added -{arm,aarch64}-enable-atomic-tidy options, so that
existing fragile tests aren't perturbed too much by the change. Many
of them either rely on undef/unreachable too pervasively to be
restored to something well-defined (particularly while making sure
they test the same obscure assert from many years ago), or depend on a
particular CFG shape, which is disrupted by SimplifyCFG.

rdar://problem/16227836

llvm-svn: 209883
2014-05-30 10:09:59 +00:00

85 lines
2.0 KiB
LLVM

; RUN: llc -verify-machineinstrs -o - %s -mtriple=arm64-apple-ios7.0 -aarch64-atomic-cfg-tidy=0 | FileCheck %s --check-prefix=CHECK
; RUN: llc -verify-machineinstrs < %s -mtriple=aarch64-none-linux-gnu -mattr=-fp-armv8 -aarch64-atomic-cfg-tidy=0 | FileCheck --check-prefix=CHECK-NOFP %s
define i32 @test_select_i32(i1 %bit, i32 %a, i32 %b) {
; CHECK-LABEL: test_select_i32:
%val = select i1 %bit, i32 %a, i32 %b
; CHECK: tst w0, #0x1
; CHECK-NEXT: csel w0, w1, w2, ne
ret i32 %val
}
define i64 @test_select_i64(i1 %bit, i64 %a, i64 %b) {
; CHECK-LABEL: test_select_i64:
%val = select i1 %bit, i64 %a, i64 %b
; CHECK: tst w0, #0x1
; CHECK-NEXT: csel x0, x1, x2, ne
ret i64 %val
}
define float @test_select_float(i1 %bit, float %a, float %b) {
; CHECK-LABEL: test_select_float:
%val = select i1 %bit, float %a, float %b
; CHECK: tst w0, #0x1
; CHECK-NEXT: fcsel s0, s0, s1, ne
; CHECK-NOFP-NOT: fcsel
ret float %val
}
define double @test_select_double(i1 %bit, double %a, double %b) {
; CHECK-LABEL: test_select_double:
%val = select i1 %bit, double %a, double %b
; CHECK: tst w0, #0x1
; CHECK-NEXT: fcsel d0, d0, d1, ne
; CHECK-NOFP-NOT: fcsel
ret double %val
}
define i32 @test_brcond(i1 %bit) {
; CHECK-LABEL: test_brcond:
br i1 %bit, label %true, label %false
; CHECK: tbz {{w[0-9]+}}, #0, {{.?LBB}}
true:
ret i32 0
false:
ret i32 42
}
define i1 @test_setcc_float(float %lhs, float %rhs) {
; CHECK: test_setcc_float
%val = fcmp oeq float %lhs, %rhs
; CHECK: fcmp s0, s1
; CHECK: cset w0, eq
; CHECK-NOFP-NOT: fcmp
ret i1 %val
}
define i1 @test_setcc_double(double %lhs, double %rhs) {
; CHECK: test_setcc_double
%val = fcmp oeq double %lhs, %rhs
; CHECK: fcmp d0, d1
; CHECK: cset w0, eq
; CHECK-NOFP-NOT: fcmp
ret i1 %val
}
define i1 @test_setcc_i32(i32 %lhs, i32 %rhs) {
; CHECK: test_setcc_i32
%val = icmp ugt i32 %lhs, %rhs
; CHECK: cmp w0, w1
; CHECK: cset w0, hi
ret i1 %val
}
define i1 @test_setcc_i64(i64 %lhs, i64 %rhs) {
; CHECK: test_setcc_i64
%val = icmp ne i64 %lhs, %rhs
; CHECK: cmp x0, x1
; CHECK: cset w0, ne
ret i1 %val
}