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https://github.com/c64scene-ar/llvm-6502.git
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2fabd464ae
ops. This is a rewrite of the IV simplification algorithm used by -disable-iv-rewrite. To avoid perturbing the default mode, I temporarily split the driver and created SimplifyIVUsersNoRewrite. The idea is to avoid doing opcode/pattern matching inside IndVarSimplify. SCEV already does it. We want to optimize with the full generality of SCEV, but optimize def-use chains top down on-demand rather than rewriting the entire expression bottom-up. This was easy to do for operations that SCEV can prove are identity function. So we're now eliminating bitmasks and zero extends this way. A result of this rewrite is that indvars -disable-iv-rewrite no longer requires IVUsers. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@133502 91177308-0d34-0410-b5e6-96231b3b80d8
35 lines
931 B
LLVM
35 lines
931 B
LLVM
; RUN: opt < %s -indvars -S | FileCheck %s
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; RUN: opt < %s -indvars -disable-iv-rewrite -S | FileCheck %s
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; CHECK-NOT: and
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; CHECK-NOT: zext
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target datalayout = "-p:64:64:64-n:32:64"
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define void @foo(double* %d, i64 %n) nounwind {
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entry:
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br label %loop
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loop:
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%indvar = phi i64 [ 0, %entry ], [ %indvar.next, %loop ]
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%indvar.i8 = and i64 %indvar, 255
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%t0 = getelementptr double* %d, i64 %indvar.i8
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%t1 = load double* %t0
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%t2 = fmul double %t1, 0.1
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store double %t2, double* %t0
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%indvar.i24 = and i64 %indvar, 16777215
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%t3 = getelementptr double* %d, i64 %indvar.i24
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%t4 = load double* %t3
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%t5 = fmul double %t4, 2.3
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store double %t5, double* %t3
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%t6 = getelementptr double* %d, i64 %indvar
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%t7 = load double* %t6
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%t8 = fmul double %t7, 4.5
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store double %t8, double* %t6
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%indvar.next = add i64 %indvar, 1
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%exitcond = icmp eq i64 %indvar.next, 10
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br i1 %exitcond, label %return, label %loop
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return:
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ret void
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}
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