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https://github.com/c64scene-ar/llvm-6502.git
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50d4008b47
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
41 lines
1.8 KiB
LLVM
41 lines
1.8 KiB
LLVM
; RUN: opt -S -loop-reduce < %s | FileCheck %s
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; Complex addressing mode are costly.
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; Make loop-reduce prefer unscaled accesses.
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; On X86, reg1 + 1*reg2 has the same cost as reg1 + 8*reg2.
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; Therefore, LSR currently prefers to fold as much computation as possible
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; in the addressing mode.
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; <rdar://problem/16730541>
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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"
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target triple = "x86_64-apple-macosx"
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define void @mulDouble(double* nocapture %a, double* nocapture %b, double* nocapture %c) {
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; CHECK: @mulDouble
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entry:
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br label %for.body
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for.body: ; preds = %for.body, %entry
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; CHECK: [[IV:%[^ ]+]] = phi i64 [ [[IVNEXT:%[^,]+]], %for.body ], [ 0, %entry ]
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; Only one induction variable should have been generated.
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; CHECK-NOT: phi
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%indvars.iv = phi i64 [ 1, %entry ], [ %indvars.iv.next, %for.body ]
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%tmp = add nsw i64 %indvars.iv, -1
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%arrayidx = getelementptr inbounds double* %b, i64 %tmp
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%tmp1 = load double* %arrayidx, align 8
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; The induction variable should carry the scaling factor: 1.
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; CHECK: [[IVNEXT]] = add nuw nsw i64 [[IV]], 1
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%indvars.iv.next = add i64 %indvars.iv, 1
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%arrayidx2 = getelementptr inbounds double* %c, i64 %indvars.iv.next
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%tmp2 = load double* %arrayidx2, align 8
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%mul = fmul double %tmp1, %tmp2
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%arrayidx4 = getelementptr inbounds double* %a, i64 %indvars.iv
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store double %mul, double* %arrayidx4, align 8
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%lftr.wideiv = trunc i64 %indvars.iv.next to i32
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; Comparison should be 19 * 1 = 19.
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; CHECK: icmp eq i32 {{%[^,]+}}, 19
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%exitcond = icmp eq i32 %lftr.wideiv, 20
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br i1 %exitcond, label %for.end, label %for.body
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for.end: ; preds = %for.body
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ret void
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}
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