5db6ffd76f
BeforeBB
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v
GuardBB
/ \
__ PreHeaderBB \
/ \ / |
latch HeaderBB |
\ / \ /
< \ /
\ /
ExitBB
This does not only remove the need for an explicit loop rotate pass, but it also
gives us the possibility to skip the construction of the guard condition in case
the loop is known to be executed at least once. We do not yet exploit this, but
by implementing this analysis in the isl code generator we should be able to
remove more guards than the generic loop rotate pass can. Another point is that
loop rotation can introduce additional PHI nodes, which may hide that a loop can
be executed in parallel. This change avoids this complication and will make it
easier to move the openmp code generation into a separate pass.
llvm-svn: 181986
59 lines
1.9 KiB
LLVM
59 lines
1.9 KiB
LLVM
; RUN: opt %loadPolly -polly-ast -analyze < %s | FileCheck %s
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; RUN: opt %loadPolly -polly-codegen-isl -S < %s | FileCheck %s -check-prefix=CODEGEN
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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"
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target triple = "x86_64-pc-linux-gnu"
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@A = common global [1024 x i32] zeroinitializer
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define void @bar(i64 %n) {
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start:
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fence seq_cst
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br label %loop.header
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loop.header:
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%i = phi i64 [ 0, %start ], [ %i.next, %loop.backedge ]
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%scevgep = getelementptr [1024 x i32]* @A, i64 0, i64 %i
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%exitcond = icmp ne i64 %i, %n
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br i1 %exitcond, label %loop.body, label %ret
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loop.body:
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store i32 1, i32* %scevgep
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br label %loop.backedge
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loop.backedge:
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%i.next = add nsw i64 %i, 1
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br label %loop.header
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ret:
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fence seq_cst
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ret void
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}
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; CHECK: for (int c1 = 0; c1 < n; c1 += 1)
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; CHECK: Stmt_loop_body(c1)
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; CODEGEN: polly.start:
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; CODEGEN: br label %polly.loop_if
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; CODEGEN: polly.loop_exit:
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; CODEGEN: br label %polly.merge_new_and_old
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; CODEGEN: polly.loop_if:
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; CODEGEN: %polly.loop_guard = icmp slt i64 0, %n
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; CODEGEN: br i1 %polly.loop_guard, label %polly.loop_preheader, label %polly.loop_exit
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; CODEGEN: polly.loop_header:
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; CODEGEN: %polly.indvar = phi i64 [ 0, %polly.loop_preheader ], [ %polly.indvar_next, %polly.stmt.loop.body ]
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; CODEGEN: br label %polly.stmt.loop.body
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; CODEGEN: polly.stmt.loop.body:
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; CODEGEN: %p_scevgep.moved.to.loop.body = getelementptr [1024 x i32]* @A, i64 0, i64 %polly.indvar
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; CODEGEN: store i32 1, i32* %p_scevgep.moved.to.loop.body
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; CODEGEN: %polly.indvar_next = add nsw i64 %polly.indvar, 1
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; CODEGEN: %polly.adjust_ub = sub i64 %n, 1
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; CODEGEN: %polly.loop_cond = icmp slt i64 %polly.indvar, %polly.adjust_ub
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; CODEGEN: br i1 %polly.loop_cond, label %polly.loop_header, label %polly.loop_exit
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; CODEGEN: polly.loop_preheader:
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; CODEGENL br label %polly.loop_header
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