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llvm-6502/test/Analysis/BasicAA/phi-speculation.ll

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BasicAA: Recognize cyclic NoAlias phis Enhances basic alias analysis to recognize phis whose first incoming values are NoAlias and whose other incoming values are just the phi node itself through some amount of recursion. Example: With this change basicaa reports that ptr_phi and ptr_phi2 do not alias each other. bb: ptr = ptr2 + 1 loop: ptr_phi = phi [bb, ptr], [loop, ptr_plus_one] ptr2_phi = phi [bb, ptr2], [loop, ptr2_plus_one] ... ptr_plus_one = gep ptr_phi, 1 ptr2_plus_one = gep ptr2_phi, 1 This enables the elimination of one load in code like the following: extern int foo; int test_noalias(int *ptr, int num, int* coeff) { int *ptr2 = ptr; int result = (*ptr++) * (*coeff--); while (num--) { *ptr2++ = *ptr; result += (*coeff--) * (*ptr++); } *ptr = foo; return result; } Part 2/2 of fix for PR13564. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@163319 91177308-0d34-0410-b5e6-96231b3b80d8
2012-09-06 14:41:53 +00:00
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"
; RUN: opt < %s -basicaa -aa-eval -print-all-alias-modref-info -disable-output 2>&1 | FileCheck %s
; ptr_phi and ptr2_phi do not alias.
Optimistically analyse Phi cycles Analyse Phis under the starting assumption that they are NoAlias. Recursively look at their inputs. If they MayAlias/MustAlias there must be an input that makes them so. Addresses bug 14351. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@169788 91177308-0d34-0410-b5e6-96231b3b80d8
2012-12-10 23:02:41 +00:00
; CHECK: test_noalias_1
BasicAA: Recognize cyclic NoAlias phis Enhances basic alias analysis to recognize phis whose first incoming values are NoAlias and whose other incoming values are just the phi node itself through some amount of recursion. Example: With this change basicaa reports that ptr_phi and ptr_phi2 do not alias each other. bb: ptr = ptr2 + 1 loop: ptr_phi = phi [bb, ptr], [loop, ptr_plus_one] ptr2_phi = phi [bb, ptr2], [loop, ptr2_plus_one] ... ptr_plus_one = gep ptr_phi, 1 ptr2_plus_one = gep ptr2_phi, 1 This enables the elimination of one load in code like the following: extern int foo; int test_noalias(int *ptr, int num, int* coeff) { int *ptr2 = ptr; int result = (*ptr++) * (*coeff--); while (num--) { *ptr2++ = *ptr; result += (*coeff--) * (*ptr++); } *ptr = foo; return result; } Part 2/2 of fix for PR13564. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@163319 91177308-0d34-0410-b5e6-96231b3b80d8
2012-09-06 14:41:53 +00:00
; CHECK: NoAlias: i32* %ptr2_phi, i32* %ptr_phi
Optimistically analyse Phi cycles Analyse Phis under the starting assumption that they are NoAlias. Recursively look at their inputs. If they MayAlias/MustAlias there must be an input that makes them so. Addresses bug 14351. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@169788 91177308-0d34-0410-b5e6-96231b3b80d8
2012-12-10 23:02:41 +00:00
define i32 @test_noalias_1(i32* %ptr2, i32 %count, i32* %coeff) {
BasicAA: Recognize cyclic NoAlias phis Enhances basic alias analysis to recognize phis whose first incoming values are NoAlias and whose other incoming values are just the phi node itself through some amount of recursion. Example: With this change basicaa reports that ptr_phi and ptr_phi2 do not alias each other. bb: ptr = ptr2 + 1 loop: ptr_phi = phi [bb, ptr], [loop, ptr_plus_one] ptr2_phi = phi [bb, ptr2], [loop, ptr2_plus_one] ... ptr_plus_one = gep ptr_phi, 1 ptr2_plus_one = gep ptr2_phi, 1 This enables the elimination of one load in code like the following: extern int foo; int test_noalias(int *ptr, int num, int* coeff) { int *ptr2 = ptr; int result = (*ptr++) * (*coeff--); while (num--) { *ptr2++ = *ptr; result += (*coeff--) * (*ptr++); } *ptr = foo; return result; } Part 2/2 of fix for PR13564. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@163319 91177308-0d34-0410-b5e6-96231b3b80d8
2012-09-06 14:41:53 +00:00
entry:
%ptr = getelementptr inbounds i32* %ptr2, i64 1
br label %while.body
while.body:
%num = phi i32 [ %count, %entry ], [ %dec, %while.body ]
%ptr_phi = phi i32* [ %ptr, %entry ], [ %ptr_inc, %while.body ]
%ptr2_phi = phi i32* [ %ptr2, %entry ], [ %ptr2_inc, %while.body ]
%result.09 = phi i32 [ 0 , %entry ], [ %add, %while.body ]
%dec = add nsw i32 %num, -1
%0 = load i32* %ptr_phi, align 4
store i32 %0, i32* %ptr2_phi, align 4
%1 = load i32* %coeff, align 4
%2 = load i32* %ptr_phi, align 4
%mul = mul nsw i32 %1, %2
%add = add nsw i32 %mul, %result.09
%tobool = icmp eq i32 %dec, 0
%ptr_inc = getelementptr inbounds i32* %ptr_phi, i64 1
%ptr2_inc = getelementptr inbounds i32* %ptr2_phi, i64 1
br i1 %tobool, label %the_exit, label %while.body
the_exit:
ret i32 %add
}
Optimistically analyse Phi cycles Analyse Phis under the starting assumption that they are NoAlias. Recursively look at their inputs. If they MayAlias/MustAlias there must be an input that makes them so. Addresses bug 14351. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@169788 91177308-0d34-0410-b5e6-96231b3b80d8
2012-12-10 23:02:41 +00:00
; CHECK: test_noalias_2
; CHECK: NoAlias: i32* %ptr_outer_phi, i32* %ptr_outer_phi2
; CHECK: NoAlias: i32* %ptr2_phi, i32* %ptr_phi
define i32 @test_noalias_2(i32* %ptr2, i32 %count, i32* %coeff) {
entry:
%ptr = getelementptr inbounds i32* %ptr2, i64 1
br label %outer.while.header
outer.while.header:
%ptr_outer_phi = phi i32* [%ptr_inc_outer, %outer.while.backedge], [ %ptr, %entry]
%ptr_outer_phi2 = phi i32* [%ptr2_inc_outer, %outer.while.backedge], [ %ptr2, %entry]
%num.outer = phi i32 [ %count, %entry ], [ %dec.outer, %outer.while.backedge ]
br label %while.body
while.body:
%num = phi i32 [ %count, %outer.while.header ], [ %dec, %while.body ]
%ptr_phi = phi i32* [ %ptr_outer_phi, %outer.while.header ], [ %ptr_inc, %while.body ]
%ptr2_phi = phi i32* [ %ptr_outer_phi2, %outer.while.header ], [ %ptr2_inc, %while.body ]
%result.09 = phi i32 [ 0 , %outer.while.header ], [ %add, %while.body ]
%dec = add nsw i32 %num, -1
%0 = load i32* %ptr_phi, align 4
store i32 %0, i32* %ptr2_phi, align 4
%1 = load i32* %coeff, align 4
%2 = load i32* %ptr_phi, align 4
%mul = mul nsw i32 %1, %2
%add = add nsw i32 %mul, %result.09
%tobool = icmp eq i32 %dec, 0
%ptr_inc = getelementptr inbounds i32* %ptr_phi, i64 1
%ptr2_inc = getelementptr inbounds i32* %ptr2_phi, i64 1
br i1 %tobool, label %outer.while.backedge, label %while.body
outer.while.backedge:
%ptr_inc_outer = getelementptr inbounds i32* %ptr_phi, i64 1
%ptr2_inc_outer = getelementptr inbounds i32* %ptr2_phi, i64 1
%dec.outer = add nsw i32 %num.outer, -1
%br.cond = icmp eq i32 %dec.outer, 0
br i1 %br.cond, label %the_exit, label %outer.while.header
the_exit:
ret i32 %add
}
; CHECK: test_noalias_3
; CHECK: MayAlias: i8* %ptr2_phi, i8* %ptr_phi
define i32 @test_noalias_3(i8* noalias %x, i8* noalias %y, i8* noalias %z,
i32 %count) {
entry:
br label %while.body
while.body:
%num = phi i32 [ %count, %entry ], [ %dec, %while.body ]
%ptr_phi = phi i8* [ %x, %entry ], [ %z, %while.body ]
%ptr2_phi = phi i8* [ %y, %entry ], [ %ptr_phi, %while.body ]
%dec = add nsw i32 %num, -1
%tobool = icmp eq i32 %dec, 0
br i1 %tobool, label %the_exit, label %while.body
the_exit:
ret i32 1
}
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