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llvm-mirror/test/Analysis/BasicAA/phi-loop.ll
David Green 9fdafb1a2b [BasicAA] Enable -basic-aa-recphi by default
This option was added a while back, to help improve AA around pointer
phi loops. It looks for phi(gep(phi, const), x) loops, checking if x can
then prove more precise aliasing info.

Differential Revision: https://reviews.llvm.org/D82998
2020-08-04 10:43:42 +01:00

76 lines
2.8 KiB
LLVM

; RUN: opt < %s -basic-aa -gvn -S | FileCheck %s
;
; Check that section->word_ofs doesn't get reloaded in every iteration of the
; for loop.
;
; Code:
;
; typedef struct {
; unsigned num_words;
; unsigned word_ofs;
; const unsigned *data;
; } section_t;
;
;
; void test2(const section_t * restrict section, unsigned * restrict dst) {;
; while (section->data != NULL) {
; const unsigned *src = section->data;
; for (unsigned i=0; i < section->num_words; ++i) {
; dst[section->word_ofs + i] = src[i];
; }
;
; ++section;
; }
; }
;
; CHECK-LABEL: for.body:
; CHECK-NOT: load i32, i32* %word_ofs
%struct.section_t = type { i32, i32, i32* }
define void @test2(%struct.section_t* noalias nocapture readonly %section, i32* noalias nocapture %dst) {
entry:
%data13 = getelementptr inbounds %struct.section_t, %struct.section_t* %section, i32 0, i32 2
%0 = load i32*, i32** %data13, align 4
%cmp14 = icmp eq i32* %0, null
br i1 %cmp14, label %while.end, label %for.cond.preheader
for.cond.preheader: ; preds = %entry, %for.end
%1 = phi i32* [ %6, %for.end ], [ %0, %entry ]
%section.addr.015 = phi %struct.section_t* [ %incdec.ptr, %for.end ], [ %section, %entry ]
%num_words = getelementptr inbounds %struct.section_t, %struct.section_t* %section.addr.015, i32 0, i32 0
%2 = load i32, i32* %num_words, align 4
%cmp211 = icmp eq i32 %2, 0
br i1 %cmp211, label %for.end, label %for.body.lr.ph
for.body.lr.ph: ; preds = %for.cond.preheader
%word_ofs = getelementptr inbounds %struct.section_t, %struct.section_t* %section.addr.015, i32 0, i32 1
br label %for.body
for.body: ; preds = %for.body.lr.ph, %for.body
%arrayidx.phi = phi i32* [ %1, %for.body.lr.ph ], [ %arrayidx.inc, %for.body ]
%i.012 = phi i32 [ 0, %for.body.lr.ph ], [ %inc, %for.body ]
%3 = load i32, i32* %arrayidx.phi, align 4
%4 = load i32, i32* %word_ofs, align 4
%add = add i32 %4, %i.012
%arrayidx3 = getelementptr inbounds i32, i32* %dst, i32 %add
store i32 %3, i32* %arrayidx3, align 4
%inc = add i32 %i.012, 1
%5 = load i32, i32* %num_words, align 4
%cmp2 = icmp ult i32 %inc, %5
%arrayidx.inc = getelementptr i32, i32* %arrayidx.phi, i32 1
br i1 %cmp2, label %for.body, label %for.end
for.end: ; preds = %for.body, %for.cond.preheader
%incdec.ptr = getelementptr inbounds %struct.section_t, %struct.section_t* %section.addr.015, i32 1
%data = getelementptr inbounds %struct.section_t, %struct.section_t* %section.addr.015, i32 1, i32 2
%6 = load i32*, i32** %data, align 4
%cmp = icmp eq i32* %6, null
br i1 %cmp, label %while.end, label %for.cond.preheader
while.end: ; preds = %for.end, %entry
ret void
}