ed6a4acc7f
Summary: This pass detangles induction variables from functions, which take variables by reference. Most fortran functions compiled with gfortran pass variables by reference. Unfortunately a common pattern, printf calls of induction variables, prevent in this situation the promotion of the induction variable to a register, which again inhibits any kind of loop analysis. To work around this issue we developed a specialized pass which introduces separate alloca slots for known-read-only references, which indicate the mem2reg pass that the induction variables can be promoted to registers and consquently enable SCEV to work. We currently hardcode the information that a function _gfortran_transfer_integer_write does not read its second parameter, as dragonegg does not add the right annotations and we cannot change old dragonegg releases. Hopefully flang will produce the right annotations. Reviewers: Meinersbur, bollu, singam-sanjay Reviewed By: bollu Subscribers: mgorny, pollydev, llvm-commits Tags: #polly Differential Revision: https://reviews.llvm.org/D36800 llvm-svn: 311066
41 lines
1.6 KiB
LLVM
41 lines
1.6 KiB
LLVM
; RUN: opt %loadPolly -polly-rewrite-byref-params -S < %s \
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; RUN: | FileCheck %s
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; Verify that we rewrite the read-only by-reference into a separate alloca slot.
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; This is useful in case %j3 is an induction variable, which should be promoted
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; by -mem2reg into a register.
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; CHECK: define void @foo(%struct.__st_parameter_dt* %p) {
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; CHECK-NEXT: entry:
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; CHECK-NEXT: %polly_byref_alloca_j3 = alloca i32
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; CHECK-NEXT: %j3 = alloca i32, align 4
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; CHECK-NEXT: %tmp = bitcast i32* %j3 to i8*
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; CHECK-NEXT: br label %bb
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; CHECK: bb: ; preds = %entry
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; CHECK-NEXT: %polly_byref_load_j3 = load i32, i32* %j3
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; CHECK-NEXT: store i32 %polly_byref_load_j3, i32* %polly_byref_alloca_j3
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; CHECK-NEXT: %polly_byref_cast_j3 = bitcast i32* %polly_byref_alloca_j3 to i8*
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; CHECK-NEXT: call void @_gfortran_transfer_integer_write(%struct.__st_parameter_dt* %p, i8* %polly_byref_cast_j3, i32 4)
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; CHECK-NEXT: ret void
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; CHECK-NEXT: }
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target datalayout = "e-p:64:64:64-S128-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f16:16:16-f32:32:32-f64:64:64-f128:128:128-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-unknown-linux-gnu"
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%struct.__st_parameter_dt = type { }
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declare void @_gfortran_transfer_integer_write(%struct.__st_parameter_dt*, i8*, i32)
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define void @foo(%struct.__st_parameter_dt* %p) {
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entry:
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%j3 = alloca i32, align 4
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%tmp = bitcast i32* %j3 to i8*
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br label %bb
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bb:
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call void @_gfortran_transfer_integer_write(%struct.__st_parameter_dt* %p, i8* %tmp, i32 4)
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ret void
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}
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