llvm-6502/test/CodeGen/X86/avoid_complex_am.ll
Quentin Colombet 50d4008b47 [LSR] Canonicalize reg1 + ... + regN into reg1 + ... + 1*regN.
This commit introduces a canonical representation for the formulae.
Basically, as soon as a formula has more that one base register, the scaled
register field is used for one of them. The register put into the scaled
register is preferably a loop variant.
The commit refactors how the formulae are built in order to produce such
representation.
This yields a more accurate, but still perfectible, cost model.

<rdar://problem/16731508>


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@209230 91177308-0d34-0410-b5e6-96231b3b80d8
2014-05-20 19:25:04 +00:00

41 lines
1.8 KiB
LLVM

; RUN: opt -S -loop-reduce < %s | FileCheck %s
; Complex addressing mode are costly.
; Make loop-reduce prefer unscaled accesses.
; On X86, reg1 + 1*reg2 has the same cost as reg1 + 8*reg2.
; Therefore, LSR currently prefers to fold as much computation as possible
; in the addressing mode.
; <rdar://problem/16730541>
target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128"
target triple = "x86_64-apple-macosx"
define void @mulDouble(double* nocapture %a, double* nocapture %b, double* nocapture %c) {
; CHECK: @mulDouble
entry:
br label %for.body
for.body: ; preds = %for.body, %entry
; CHECK: [[IV:%[^ ]+]] = phi i64 [ [[IVNEXT:%[^,]+]], %for.body ], [ 0, %entry ]
; Only one induction variable should have been generated.
; CHECK-NOT: phi
%indvars.iv = phi i64 [ 1, %entry ], [ %indvars.iv.next, %for.body ]
%tmp = add nsw i64 %indvars.iv, -1
%arrayidx = getelementptr inbounds double* %b, i64 %tmp
%tmp1 = load double* %arrayidx, align 8
; The induction variable should carry the scaling factor: 1.
; CHECK: [[IVNEXT]] = add nuw nsw i64 [[IV]], 1
%indvars.iv.next = add i64 %indvars.iv, 1
%arrayidx2 = getelementptr inbounds double* %c, i64 %indvars.iv.next
%tmp2 = load double* %arrayidx2, align 8
%mul = fmul double %tmp1, %tmp2
%arrayidx4 = getelementptr inbounds double* %a, i64 %indvars.iv
store double %mul, double* %arrayidx4, align 8
%lftr.wideiv = trunc i64 %indvars.iv.next to i32
; Comparison should be 19 * 1 = 19.
; CHECK: icmp eq i32 {{%[^,]+}}, 19
%exitcond = icmp eq i32 %lftr.wideiv, 20
br i1 %exitcond, label %for.end, label %for.body
for.end: ; preds = %for.body
ret void
}