mirror of
https://github.com/c64scene-ar/llvm-6502.git
synced 2024-12-15 20:29:48 +00:00
84fca61ca5
This revision attempts to recognize following population-count pattern:
while(a) { c++; ... ; a &= a - 1; ... },
where <c> and <a>could be used multiple times in the loop body.
TODO: On X8664 and ARM, __buildin_ctpop() are not expanded to a efficent
instruction sequence, which need to be improved in the following commits.
Reviewed by Nadav, really appreciate!
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168931 91177308-0d34-0410-b5e6-96231b3b80d8
77 lines
2.5 KiB
LLVM
77 lines
2.5 KiB
LLVM
; RUN: opt -loop-idiom < %s -mtriple=x86_64-apple-darwin -mcpu=corei7 -S | FileCheck %s
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;To recognize this pattern:
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;int popcount(unsigned long long a) {
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; int c = 0;
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; while (a) {
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; c++;
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; a &= a - 1;
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; }
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; return c;
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;}
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;
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; CHECK: entry
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; CHECK: llvm.ctpop.i64
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; CHECK: ret
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define i32 @popcount(i64 %a) nounwind uwtable readnone ssp {
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entry:
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%tobool3 = icmp eq i64 %a, 0
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br i1 %tobool3, label %while.end, label %while.body
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while.body: ; preds = %entry, %while.body
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%c.05 = phi i32 [ %inc, %while.body ], [ 0, %entry ]
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%a.addr.04 = phi i64 [ %and, %while.body ], [ %a, %entry ]
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%inc = add nsw i32 %c.05, 1
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%sub = add i64 %a.addr.04, -1
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%and = and i64 %sub, %a.addr.04
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%tobool = icmp eq i64 %and, 0
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br i1 %tobool, label %while.end, label %while.body
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while.end: ; preds = %while.body, %entry
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%c.0.lcssa = phi i32 [ 0, %entry ], [ %inc, %while.body ]
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ret i32 %c.0.lcssa
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}
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; To recognize this pattern:
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;int popcount(unsigned long long a, int mydata1, int mydata2) {
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; int c = 0;
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; while (a) {
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; c++;
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; a &= a - 1;
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; mydata1 *= c;
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; mydata2 *= (int)a;
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; }
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; return c + mydata1 + mydata2;
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;}
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; CHECK: entry
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; CHECK: llvm.ctpop.i64
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; CHECK: ret
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define i32 @popcount2(i64 %a, i32 %mydata1, i32 %mydata2) nounwind uwtable readnone ssp {
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entry:
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%tobool9 = icmp eq i64 %a, 0
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br i1 %tobool9, label %while.end, label %while.body
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while.body: ; preds = %entry, %while.body
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%c.013 = phi i32 [ %inc, %while.body ], [ 0, %entry ]
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%mydata2.addr.012 = phi i32 [ %mul1, %while.body ], [ %mydata2, %entry ]
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%mydata1.addr.011 = phi i32 [ %mul, %while.body ], [ %mydata1, %entry ]
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%a.addr.010 = phi i64 [ %and, %while.body ], [ %a, %entry ]
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%inc = add nsw i32 %c.013, 1
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%sub = add i64 %a.addr.010, -1
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%and = and i64 %sub, %a.addr.010
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%mul = mul nsw i32 %inc, %mydata1.addr.011
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%conv = trunc i64 %and to i32
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%mul1 = mul nsw i32 %conv, %mydata2.addr.012
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%tobool = icmp eq i64 %and, 0
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br i1 %tobool, label %while.end, label %while.body
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while.end: ; preds = %while.body, %entry
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%c.0.lcssa = phi i32 [ 0, %entry ], [ %inc, %while.body ]
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%mydata2.addr.0.lcssa = phi i32 [ %mydata2, %entry ], [ %mul1, %while.body ]
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%mydata1.addr.0.lcssa = phi i32 [ %mydata1, %entry ], [ %mul, %while.body ]
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%add = add i32 %mydata2.addr.0.lcssa, %mydata1.addr.0.lcssa
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%add2 = add i32 %add, %c.0.lcssa
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ret i32 %add2
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}
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