llvm-6502/test/CodeGen/X86/2009-04-20-LinearScanOpt.ll
Evan Cheng 206d1856ad Added a linearscan register allocation optimization. When the register allocator spill an interval with multiple uses in the same basic block, it creates a different virtual register for each of the reloads. e.g.
%reg1498<def> = MOV32rm %reg1024, 1, %reg0, 12, %reg0, Mem:LD(4,4) [sunkaddr39 + 0]
        %reg1506<def> = MOV32rm %reg1024, 1, %reg0, 8, %reg0, Mem:LD(4,4) [sunkaddr42 + 0]
        %reg1486<def> = MOV32rr %reg1506
        %reg1486<def> = XOR32rr %reg1486, %reg1498, %EFLAGS<imp-def,dead>
        %reg1510<def> = MOV32rm %reg1024, 1, %reg0, 4, %reg0, Mem:LD(4,4) [sunkaddr45 + 0]

=>

        %reg1498<def> = MOV32rm %reg2036, 1, %reg0, 12, %reg0, Mem:LD(4,4) [sunkaddr39 + 0]
        %reg1506<def> = MOV32rm %reg2037, 1, %reg0, 8, %reg0, Mem:LD(4,4) [sunkaddr42 + 0]
        %reg1486<def> = MOV32rr %reg1506
        %reg1486<def> = XOR32rr %reg1486, %reg1498, %EFLAGS<imp-def,dead>
        %reg1510<def> = MOV32rm %reg2038, 1, %reg0, 4, %reg0, Mem:LD(4,4) [sunkaddr45 + 0]

From linearscan's point of view, each of reg2036, 2037, and 2038 are separate registers, each is "killed" after a single use. The reloaded register is available and it's often clobbered right away. e.g. In thise case reg1498 is allocated EAX while reg2036 is allocated RAX. This means we end up with multiple reloads from the same stack slot in the same basic block.

Now linearscan recognize there are other reloads from same SS in the same BB. So it'll "downgrade" RAX (and its aliases) after reg2036 is allocated until the next reload (reg2037) is done. This greatly increase the likihood reloads from SS are reused.

This speeds up sha1 from OpenSSL by 5.8%. It is also an across the board win for SPEC2000 and 2006.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@69585 91177308-0d34-0410-b5e6-96231b3b80d8
2009-04-20 08:01:12 +00:00

122 lines
7.6 KiB
LLVM

; RUN: llvm-as < %s | llc -mtriple=x86_64-apple-darwin10.0 -relocation-model=pic -disable-fp-elim -stats |& grep {Number of registers downgraded}
; rdar://6802189
; Test if linearscan is unfavoring registers for allocation to allow more reuse
; of reloads from stack slots.
%struct.SHA_CTX = type { i32, i32, i32, i32, i32, i32, i32, [16 x i32], i32 }
define fastcc void @sha1_block_data_order(%struct.SHA_CTX* nocapture %c, i8* %p, i64 %num) nounwind {
entry:
br label %bb
bb: ; preds = %bb, %entry
%asmtmp511 = tail call i32 asm "roll $1,$0", "=r,I,0,~{dirflag},~{fpsr},~{flags},~{cc}"(i32 1, i32 0) nounwind ; <i32> [#uses=3]
%asmtmp513 = tail call i32 asm "roll $1,$0", "=r,I,0,~{dirflag},~{fpsr},~{flags},~{cc}"(i32 30, i32 0) nounwind ; <i32> [#uses=2]
%asmtmp516 = tail call i32 asm "roll $1,$0", "=r,I,0,~{dirflag},~{fpsr},~{flags},~{cc}"(i32 30, i32 0) nounwind ; <i32> [#uses=1]
%asmtmp517 = tail call i32 asm "roll $1,$0", "=r,I,0,~{dirflag},~{fpsr},~{flags},~{cc}"(i32 1, i32 0) nounwind ; <i32> [#uses=2]
%0 = xor i32 0, %asmtmp513 ; <i32> [#uses=0]
%1 = add i32 0, %asmtmp517 ; <i32> [#uses=1]
%2 = add i32 %1, 0 ; <i32> [#uses=1]
%3 = add i32 %2, 0 ; <i32> [#uses=1]
%asmtmp519 = tail call i32 asm "roll $1,$0", "=r,I,0,~{dirflag},~{fpsr},~{flags},~{cc}"(i32 30, i32 0) nounwind ; <i32> [#uses=1]
%4 = xor i32 0, %asmtmp511 ; <i32> [#uses=1]
%asmtmp520 = tail call i32 asm "roll $1,$0", "=r,I,0,~{dirflag},~{fpsr},~{flags},~{cc}"(i32 1, i32 %4) nounwind ; <i32> [#uses=2]
%5 = xor i32 0, %asmtmp516 ; <i32> [#uses=1]
%6 = xor i32 %5, %asmtmp519 ; <i32> [#uses=1]
%7 = add i32 %asmtmp513, -899497514 ; <i32> [#uses=1]
%8 = add i32 %7, %asmtmp520 ; <i32> [#uses=1]
%9 = add i32 %8, %6 ; <i32> [#uses=1]
%10 = add i32 %9, 0 ; <i32> [#uses=1]
%asmtmp523 = tail call i32 asm "roll $1,$0", "=r,I,0,~{dirflag},~{fpsr},~{flags},~{cc}"(i32 1, i32 0) nounwind ; <i32> [#uses=1]
%asmtmp525 = tail call i32 asm "roll $1,$0", "=r,I,0,~{dirflag},~{fpsr},~{flags},~{cc}"(i32 30, i32 %3) nounwind ; <i32> [#uses=2]
%11 = xor i32 0, %asmtmp525 ; <i32> [#uses=1]
%12 = add i32 0, %11 ; <i32> [#uses=1]
%13 = add i32 %12, 0 ; <i32> [#uses=2]
%asmtmp528 = tail call i32 asm "roll $1,$0", "=r,I,0,~{dirflag},~{fpsr},~{flags},~{cc}"(i32 30, i32 %10) nounwind ; <i32> [#uses=1]
%14 = xor i32 0, %asmtmp520 ; <i32> [#uses=1]
%asmtmp529 = tail call i32 asm "roll $1,$0", "=r,I,0,~{dirflag},~{fpsr},~{flags},~{cc}"(i32 1, i32 %14) nounwind ; <i32> [#uses=1]
%asmtmp530 = tail call i32 asm "roll $1,$0", "=r,I,0,~{dirflag},~{fpsr},~{flags},~{cc}"(i32 5, i32 %13) nounwind ; <i32> [#uses=1]
%15 = add i32 0, %asmtmp530 ; <i32> [#uses=1]
%16 = xor i32 0, %asmtmp523 ; <i32> [#uses=1]
%asmtmp532 = tail call i32 asm "roll $1,$0", "=r,I,0,~{dirflag},~{fpsr},~{flags},~{cc}"(i32 1, i32 %16) nounwind ; <i32> [#uses=2]
%asmtmp533 = tail call i32 asm "roll $1,$0", "=r,I,0,~{dirflag},~{fpsr},~{flags},~{cc}"(i32 5, i32 %15) nounwind ; <i32> [#uses=1]
%17 = xor i32 %13, %asmtmp528 ; <i32> [#uses=1]
%18 = xor i32 %17, 0 ; <i32> [#uses=1]
%19 = add i32 %asmtmp525, -899497514 ; <i32> [#uses=1]
%20 = add i32 %19, %asmtmp532 ; <i32> [#uses=1]
%21 = add i32 %20, %18 ; <i32> [#uses=1]
%22 = add i32 %21, %asmtmp533 ; <i32> [#uses=1]
%23 = xor i32 0, %asmtmp511 ; <i32> [#uses=1]
%24 = xor i32 %23, 0 ; <i32> [#uses=1]
%asmtmp535 = tail call i32 asm "roll $1,$0", "=r,I,0,~{dirflag},~{fpsr},~{flags},~{cc}"(i32 1, i32 %24) nounwind ; <i32> [#uses=3]
%25 = add i32 0, %asmtmp535 ; <i32> [#uses=1]
%26 = add i32 %25, 0 ; <i32> [#uses=1]
%27 = add i32 %26, 0 ; <i32> [#uses=1]
%28 = xor i32 0, %asmtmp529 ; <i32> [#uses=0]
%29 = xor i32 %22, 0 ; <i32> [#uses=1]
%30 = xor i32 %29, 0 ; <i32> [#uses=1]
%31 = add i32 0, %30 ; <i32> [#uses=1]
%32 = add i32 %31, 0 ; <i32> [#uses=3]
%asmtmp541 = tail call i32 asm "roll $1,$0", "=r,I,0,~{dirflag},~{fpsr},~{flags},~{cc}"(i32 1, i32 0) nounwind ; <i32> [#uses=2]
%asmtmp542 = tail call i32 asm "roll $1,$0", "=r,I,0,~{dirflag},~{fpsr},~{flags},~{cc}"(i32 5, i32 %32) nounwind ; <i32> [#uses=1]
%33 = add i32 0, %asmtmp541 ; <i32> [#uses=1]
%34 = add i32 %33, 0 ; <i32> [#uses=1]
%35 = add i32 %34, %asmtmp542 ; <i32> [#uses=1]
%asmtmp543 = tail call i32 asm "roll $1,$0", "=r,I,0,~{dirflag},~{fpsr},~{flags},~{cc}"(i32 30, i32 %27) nounwind ; <i32> [#uses=2]
%36 = xor i32 0, %asmtmp535 ; <i32> [#uses=0]
%37 = xor i32 %32, 0 ; <i32> [#uses=1]
%38 = xor i32 %37, %asmtmp543 ; <i32> [#uses=1]
%39 = add i32 0, %38 ; <i32> [#uses=1]
%40 = add i32 %39, 0 ; <i32> [#uses=2]
%asmtmp546 = tail call i32 asm "roll $1,$0", "=r,I,0,~{dirflag},~{fpsr},~{flags},~{cc}"(i32 30, i32 %32) nounwind ; <i32> [#uses=1]
%asmtmp547 = tail call i32 asm "roll $1,$0", "=r,I,0,~{dirflag},~{fpsr},~{flags},~{cc}"(i32 1, i32 0) nounwind ; <i32> [#uses=2]
%41 = add i32 0, -899497514 ; <i32> [#uses=1]
%42 = add i32 %41, %asmtmp547 ; <i32> [#uses=1]
%43 = add i32 %42, 0 ; <i32> [#uses=1]
%44 = add i32 %43, 0 ; <i32> [#uses=3]
%asmtmp549 = tail call i32 asm "roll $1,$0", "=r,I,0,~{dirflag},~{fpsr},~{flags},~{cc}"(i32 30, i32 %35) nounwind ; <i32> [#uses=2]
%45 = xor i32 0, %asmtmp541 ; <i32> [#uses=1]
%asmtmp550 = tail call i32 asm "roll $1,$0", "=r,I,0,~{dirflag},~{fpsr},~{flags},~{cc}"(i32 1, i32 %45) nounwind ; <i32> [#uses=2]
%asmtmp551 = tail call i32 asm "roll $1,$0", "=r,I,0,~{dirflag},~{fpsr},~{flags},~{cc}"(i32 5, i32 %44) nounwind ; <i32> [#uses=1]
%46 = xor i32 %40, %asmtmp546 ; <i32> [#uses=1]
%47 = xor i32 %46, %asmtmp549 ; <i32> [#uses=1]
%48 = add i32 %asmtmp543, -899497514 ; <i32> [#uses=1]
%49 = add i32 %48, %asmtmp550 ; <i32> [#uses=1]
%50 = add i32 %49, %47 ; <i32> [#uses=1]
%51 = add i32 %50, %asmtmp551 ; <i32> [#uses=1]
%asmtmp552 = tail call i32 asm "roll $1,$0", "=r,I,0,~{dirflag},~{fpsr},~{flags},~{cc}"(i32 30, i32 %40) nounwind ; <i32> [#uses=2]
%52 = xor i32 %44, %asmtmp549 ; <i32> [#uses=1]
%53 = xor i32 %52, %asmtmp552 ; <i32> [#uses=1]
%54 = add i32 0, %53 ; <i32> [#uses=1]
%55 = add i32 %54, 0 ; <i32> [#uses=2]
%asmtmp555 = tail call i32 asm "roll $1,$0", "=r,I,0,~{dirflag},~{fpsr},~{flags},~{cc}"(i32 30, i32 %44) nounwind ; <i32> [#uses=2]
%56 = xor i32 0, %asmtmp532 ; <i32> [#uses=1]
%57 = xor i32 %56, %asmtmp547 ; <i32> [#uses=1]
%asmtmp556 = tail call i32 asm "roll $1,$0", "=r,I,0,~{dirflag},~{fpsr},~{flags},~{cc}"(i32 1, i32 %57) nounwind ; <i32> [#uses=1]
%58 = add i32 0, %asmtmp556 ; <i32> [#uses=1]
%59 = add i32 %58, 0 ; <i32> [#uses=1]
%60 = add i32 %59, 0 ; <i32> [#uses=1]
%asmtmp558 = tail call i32 asm "roll $1,$0", "=r,I,0,~{dirflag},~{fpsr},~{flags},~{cc}"(i32 30, i32 %51) nounwind ; <i32> [#uses=1]
%61 = xor i32 %asmtmp517, %asmtmp511 ; <i32> [#uses=1]
%62 = xor i32 %61, %asmtmp535 ; <i32> [#uses=1]
%63 = xor i32 %62, %asmtmp550 ; <i32> [#uses=1]
%asmtmp559 = tail call i32 asm "roll $1,$0", "=r,I,0,~{dirflag},~{fpsr},~{flags},~{cc}"(i32 1, i32 %63) nounwind ; <i32> [#uses=1]
%64 = xor i32 %55, %asmtmp555 ; <i32> [#uses=1]
%65 = xor i32 %64, %asmtmp558 ; <i32> [#uses=1]
%asmtmp561 = tail call i32 asm "roll $1,$0", "=r,I,0,~{dirflag},~{fpsr},~{flags},~{cc}"(i32 30, i32 %55) nounwind ; <i32> [#uses=1]
%66 = add i32 %asmtmp552, -899497514 ; <i32> [#uses=1]
%67 = add i32 %66, %65 ; <i32> [#uses=1]
%68 = add i32 %67, %asmtmp559 ; <i32> [#uses=1]
%69 = add i32 %68, 0 ; <i32> [#uses=1]
%70 = add i32 %69, 0 ; <i32> [#uses=1]
store i32 %70, i32* null, align 4
%71 = add i32 0, %60 ; <i32> [#uses=1]
store i32 %71, i32* null, align 4
%72 = add i32 0, %asmtmp561 ; <i32> [#uses=1]
store i32 %72, i32* null, align 4
%73 = add i32 0, %asmtmp555 ; <i32> [#uses=1]
store i32 %73, i32* null, align 4
br label %bb
}