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llvm-6502/test/CodeGen/X86/select.ll
Andrew Trick 6ea2b9608a Allocate local registers in order for optimal coloring. 
Also avoid locals evicting locals just because they want a cheaper register.

Problem: MI Sched knows exactly how many registers we have and assumes
they can be colored. In cases where we have large blocks, usually from
unrolled loops, greedy coloring fails. This is a source of
"regressions" from the MI Scheduler on x86. I noticed this issue on
x86 where we have long chains of two-address defs in the same live
range. It's easy to see this in matrix multiplication benchmarks like
IRSmk and even the unit test misched-matmul.ll.

A fundamental difference between the LLVM register allocator and
conventional graph coloring is that in our model a live range can't
discover its neighbors, it can only verify its neighbors. That's why
we initially went for greedy coloring and added eviction to deal with
the hard cases. However, for singly defined and two-address live
ranges, we can optimally color without visiting neighbors simply by
processing the live ranges in instruction order.

Other beneficial side effects:

It is much easier to understand and debug regalloc for large blocks
when the live ranges are allocated in order. Yes, global allocation is
still very confusing, but it's nice to be able to comprehend what
happened locally.

Heuristics could be added to bias register assignment based on
instruction locality (think late register pairing, banks...).

Intuituvely this will make some test cases that are on the threshold
of register pressure more stable.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@187139 91177308-0d34-0410-b5e6-96231b3b80d8
2013-07-25 18:35:14 +00:00

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; RUN: llc < %s -mtriple=x86_64-apple-darwin10 -mcpu=generic | FileCheck %s
; RUN: llc < %s -mtriple=x86_64-apple-darwin10 -mcpu=atom | FileCheck -check-prefix=ATOM %s
; PR5757
%0 = type { i64, i32 }
define i32 @test1(%0* %p, %0* %q, i1 %r) nounwind {
%t0 = load %0* %p
%t1 = load %0* %q
%t4 = select i1 %r, %0 %t0, %0 %t1
%t5 = extractvalue %0 %t4, 1
ret i32 %t5
; CHECK-LABEL: test1:
; CHECK: cmovneq %rdi, %rsi
; CHECK: movl (%rsi), %eax
; ATOM-LABEL: test1:
; ATOM: cmovneq %rdi, %rsi
; ATOM: movl (%rsi), %eax
}
; PR2139
define i32 @test2() nounwind {
entry:
%tmp73 = tail call i1 @return_false() ; <i8> [#uses=1]
%g.0 = select i1 %tmp73, i16 0, i16 -480 ; <i16> [#uses=2]
%tmp7778 = sext i16 %g.0 to i32 ; <i32> [#uses=1]
%tmp80 = shl i32 %tmp7778, 3 ; <i32> [#uses=2]
%tmp87 = icmp sgt i32 %tmp80, 32767 ; <i1> [#uses=1]
br i1 %tmp87, label %bb90, label %bb91
bb90: ; preds = %bb84, %bb72
unreachable
bb91: ; preds = %bb84
ret i32 0
; CHECK-LABEL: test2:
; CHECK: movnew
; CHECK: movswl
; ATOM-LABEL: test2:
; ATOM: movnew
; ATOM: movswl
}
declare i1 @return_false()
;; Select between two floating point constants.
define float @test3(i32 %x) nounwind readnone {
entry:
%0 = icmp eq i32 %x, 0 ; <i1> [#uses=1]
%iftmp.0.0 = select i1 %0, float 4.200000e+01, float 2.300000e+01 ; <float> [#uses=1]
ret float %iftmp.0.0
; CHECK-LABEL: test3:
; CHECK: movss {{.*}},4), %xmm0
; ATOM-LABEL: test3:
; ATOM: movss {{.*}},4), %xmm0
}
define signext i8 @test4(i8* nocapture %P, double %F) nounwind readonly {
entry:
%0 = fcmp olt double %F, 4.200000e+01 ; <i1> [#uses=1]
%iftmp.0.0 = select i1 %0, i32 4, i32 0 ; <i32> [#uses=1]
%1 = getelementptr i8* %P, i32 %iftmp.0.0 ; <i8*> [#uses=1]
%2 = load i8* %1, align 1 ; <i8> [#uses=1]
ret i8 %2
; CHECK-LABEL: test4:
; CHECK: movsbl ({{.*}},4), %eax
; ATOM-LABEL: test4:
; ATOM: movsbl ({{.*}},4), %eax
}
define void @test5(i1 %c, <2 x i16> %a, <2 x i16> %b, <2 x i16>* %p) nounwind {
%x = select i1 %c, <2 x i16> %a, <2 x i16> %b
store <2 x i16> %x, <2 x i16>* %p
ret void
; CHECK-LABEL: test5:
; ATOM-LABEL: test5:
}
define void @test6(i32 %C, <4 x float>* %A, <4 x float>* %B) nounwind {
%tmp = load <4 x float>* %A ; <<4 x float>> [#uses=1]
%tmp3 = load <4 x float>* %B ; <<4 x float>> [#uses=2]
%tmp9 = fmul <4 x float> %tmp3, %tmp3 ; <<4 x float>> [#uses=1]
%tmp.upgrd.1 = icmp eq i32 %C, 0 ; <i1> [#uses=1]
%iftmp.38.0 = select i1 %tmp.upgrd.1, <4 x float> %tmp9, <4 x float> %tmp ; <<4 x float>> [#uses=1]
store <4 x float> %iftmp.38.0, <4 x float>* %A
ret void
; Verify that the fmul gets sunk into the one part of the diamond where it is
; needed.
; CHECK-LABEL: test6:
; CHECK: je
; CHECK: ret
; CHECK: mulps
; CHECK: ret
; ATOM-LABEL: test6:
; ATOM: je
; ATOM: ret
; ATOM: mulps
; ATOM: ret
}
; Select with fp80's
define x86_fp80 @test7(i32 %tmp8) nounwind {
%tmp9 = icmp sgt i32 %tmp8, -1 ; <i1> [#uses=1]
%retval = select i1 %tmp9, x86_fp80 0xK4005B400000000000000, x86_fp80 0xK40078700000000000000
ret x86_fp80 %retval
; CHECK-LABEL: test7:
; CHECK: leaq
; CHECK: fldt (%r{{.}}x,%r{{.}}x)
; ATOM-LABEL: test7:
; ATOM: leaq
; ATOM: fldt (%r{{.}}x,%r{{.}}x)
}
; widening select v6i32 and then a sub
define void @test8(i1 %c, <6 x i32>* %dst.addr, <6 x i32> %src1,<6 x i32> %src2) nounwind {
%x = select i1 %c, <6 x i32> %src1, <6 x i32> %src2
%val = sub <6 x i32> %x, < i32 1, i32 1, i32 1, i32 1, i32 1, i32 1 >
store <6 x i32> %val, <6 x i32>* %dst.addr
ret void
; CHECK-LABEL: test8:
; ATOM-LABEL: test8:
}
;; Test integer select between values and constants.
define i64 @test9(i64 %x, i64 %y) nounwind readnone ssp noredzone {
%cmp = icmp ne i64 %x, 0
%cond = select i1 %cmp, i64 %y, i64 -1
ret i64 %cond
; CHECK-LABEL: test9:
; CHECK: cmpq $1, %rdi
; CHECK: sbbq %rax, %rax
; CHECK: orq %rsi, %rax
; CHECK: ret
; ATOM-LABEL: test9:
; ATOM: cmpq $1, %rdi
; ATOM: sbbq %rax, %rax
; ATOM: orq %rsi, %rax
; ATOM: ret
}
;; Same as test9
define i64 @test9a(i64 %x, i64 %y) nounwind readnone ssp noredzone {
%cmp = icmp eq i64 %x, 0
%cond = select i1 %cmp, i64 -1, i64 %y
ret i64 %cond
; CHECK-LABEL: test9a:
; CHECK: cmpq $1, %rdi
; CHECK: sbbq %rax, %rax
; CHECK: orq %rsi, %rax
; CHECK: ret
; ATOM-LABEL: test9a:
; ATOM: cmpq $1, %rdi
; ATOM: sbbq %rax, %rax
; ATOM: orq %rsi, %rax
; ATOM: ret
}
define i64 @test9b(i64 %x, i64 %y) nounwind readnone ssp noredzone {
%cmp = icmp eq i64 %x, 0
%A = sext i1 %cmp to i64
%cond = or i64 %y, %A
ret i64 %cond
; CHECK-LABEL: test9b:
; CHECK: cmpq $1, %rdi
; CHECK: sbbq %rax, %rax
; CHECK: orq %rsi, %rax
; CHECK: ret
; ATOM-LABEL: test9b:
; ATOM: cmpq $1, %rdi
; ATOM: sbbq %rax, %rax
; ATOM: orq %rsi, %rax
; ATOM: ret
}
;; Select between -1 and 1.
define i64 @test10(i64 %x, i64 %y) nounwind readnone ssp noredzone {
%cmp = icmp eq i64 %x, 0
%cond = select i1 %cmp, i64 -1, i64 1
ret i64 %cond
; CHECK-LABEL: test10:
; CHECK: cmpq $1, %rdi
; CHECK: sbbq %rax, %rax
; CHECK: orq $1, %rax
; CHECK: ret
; ATOM-LABEL: test10:
; ATOM: cmpq $1, %rdi
; ATOM: sbbq %rax, %rax
; ATOM: orq $1, %rax
; ATOM: ret
}
define i64 @test11(i64 %x, i64 %y) nounwind readnone ssp noredzone {
%cmp = icmp eq i64 %x, 0
%cond = select i1 %cmp, i64 %y, i64 -1
ret i64 %cond
; CHECK-LABEL: test11:
; CHECK: cmpq $1, %rdi
; CHECK: sbbq %rax, %rax
; CHECK: notq %rax
; CHECK: orq %rsi, %rax
; CHECK: ret
; ATOM-LABEL: test11:
; ATOM: cmpq $1, %rdi
; ATOM: sbbq %rax, %rax
; ATOM: notq %rax
; ATOM: orq %rsi, %rax
; ATOM: ret
}
define i64 @test11a(i64 %x, i64 %y) nounwind readnone ssp noredzone {
%cmp = icmp ne i64 %x, 0
%cond = select i1 %cmp, i64 -1, i64 %y
ret i64 %cond
; CHECK-LABEL: test11a:
; CHECK: cmpq $1, %rdi
; CHECK: sbbq %rax, %rax
; CHECK: notq %rax
; CHECK: orq %rsi, %rax
; CHECK: ret
; ATOM-LABEL: test11a:
; ATOM: cmpq $1, %rdi
; ATOM: sbbq %rax, %rax
; ATOM: notq %rax
; ATOM: orq %rsi, %rax
; ATOM: ret
}
declare noalias i8* @_Znam(i64) noredzone
define noalias i8* @test12(i64 %count) nounwind ssp noredzone {
entry:
%A = tail call { i64, i1 } @llvm.umul.with.overflow.i64(i64 %count, i64 4)
%B = extractvalue { i64, i1 } %A, 1
%C = extractvalue { i64, i1 } %A, 0
%D = select i1 %B, i64 -1, i64 %C
%call = tail call noalias i8* @_Znam(i64 %D) nounwind noredzone
ret i8* %call
; CHECK-LABEL: test12:
; CHECK: movq $-1, %[[R:r..]]
; CHECK: mulq
; CHECK: cmovnoq %rax, %[[R]]
; CHECK: jmp __Znam
; ATOM-LABEL: test12:
; ATOM: mulq
; ATOM: movq $-1, %rdi
; ATOM: cmovnoq %rax, %rdi
; ATOM: jmp __Znam
}
declare { i64, i1 } @llvm.umul.with.overflow.i64(i64, i64) nounwind readnone
define i32 @test13(i32 %a, i32 %b) nounwind {
%c = icmp ult i32 %a, %b
%d = sext i1 %c to i32
ret i32 %d
; CHECK-LABEL: test13:
; CHECK: cmpl
; CHECK-NEXT: sbbl
; CHECK-NEXT: ret
; ATOM-LABEL: test13:
; ATOM: cmpl
; ATOM-NEXT: sbbl
; ATOM: ret
}
define i32 @test14(i32 %a, i32 %b) nounwind {
%c = icmp uge i32 %a, %b
%d = sext i1 %c to i32
ret i32 %d
; CHECK-LABEL: test14:
; CHECK: cmpl
; CHECK-NEXT: sbbl
; CHECK-NEXT: notl
; CHECK-NEXT: ret
; ATOM-LABEL: test14:
; ATOM: cmpl
; ATOM-NEXT: sbbl
; ATOM-NEXT: notl
; ATOM: ret
}
; rdar://10961709
define i32 @test15(i32 %x) nounwind {
entry:
%cmp = icmp ne i32 %x, 0
%sub = sext i1 %cmp to i32
ret i32 %sub
; CHECK-LABEL: test15:
; CHECK: negl
; CHECK: sbbl
; ATOM-LABEL: test15:
; ATOM: negl
; ATOM: sbbl
}
define i64 @test16(i64 %x) nounwind uwtable readnone ssp {
entry:
%cmp = icmp ne i64 %x, 0
%conv1 = sext i1 %cmp to i64
ret i64 %conv1
; CHECK-LABEL: test16:
; CHECK: negq
; CHECK: sbbq
; ATOM-LABEL: test16:
; ATOM: negq
; ATOM: sbbq
}
define i16 @test17(i16 %x) nounwind {
entry:
%cmp = icmp ne i16 %x, 0
%sub = sext i1 %cmp to i16
ret i16 %sub
; CHECK-LABEL: test17:
; CHECK: negw
; CHECK: sbbw
; ATOM-LABEL: test17:
; ATOM: negw
; ATOM: sbbw
}
define i8 @test18(i32 %x, i8 zeroext %a, i8 zeroext %b) nounwind {
%cmp = icmp slt i32 %x, 15
%sel = select i1 %cmp, i8 %a, i8 %b
ret i8 %sel
; CHECK-LABEL: test18:
; CHECK: cmpl $15, %edi
; CHECK: cmovgel %edx
; ATOM-LABEL: test18:
; ATOM: cmpl $15, %edi
; ATOM: cmovgel %edx
}
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