maxjhandsome
/
llvm-project
forked from OSchip/llvm-project
1
0
Fork 0
Code Issues Pull Requests Packages Releases Wiki Activity
llvm-project/polly/test/ScopInfo/unsigned-condition.ll

Ignoring revisions in .git-blame-ignore-revs. Click here to bypass and see the normal blame view.

45 lines
1.2 KiB
LLVM
Raw Normal View History

Allow unsigned comparisons With this patch we will optimistically assume that the result of an unsigned comparison is the same as the result of the same comparison interpreted as signed. llvm-svn: 267559
2016-04-26 22:33:12 +08:00
; RUN: opt %loadPolly -polly-scops -analyze < %s | FileCheck %s
Add experimental support for unsigned expressions This support is still incomplete and consequently hidden behind a switch that needs to be enabled. One problem is ATM that we incorrectly interpret very large unsigned values as negative values even if used in an unsigned comparision. llvm-svn: 225480
2015-01-09 08:01:33 +08:00
; void f(int a[], int N, unsigned P) {
; int i;
; for (i = 0; i < N; ++i)
; if (P > 42)
; a[i] = i;
; }
Allow unsigned comparisons With this patch we will optimistically assume that the result of an unsigned comparison is the same as the result of the same comparison interpreted as signed. llvm-svn: 267559
2016-04-26 22:33:12 +08:00
; The assumed context is the universe because the "signed-unsigned assumption"
; [P, N] -> { : N > 0 and P >= 0 }
; is implied by the execution domain. Thus if something is executed this
; assumption will hold.
; CHECK: Assumed Context:
; CHECK-NEXT: [P, N] -> { : }
;
; CHECK: Domain :=
; CHECK-NEXT: [P, N] -> { Stmt_store[i0] : P >= 42 and 0 <= i0 < N };
Add experimental support for unsigned expressions This support is still incomplete and consequently hidden behind a switch that needs to be enabled. One problem is ATM that we incorrectly interpret very large unsigned values as negative values even if used in an unsigned comparision. llvm-svn: 225480
2015-01-09 08:01:33 +08:00
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"
define void @f(i64* nocapture %a, i64 %N, i64 %P) nounwind {
entry:
br label %bb
bb:
%i = phi i64 [ 0, %entry ], [ %i.inc, %bb.backedge ]
%brcond = icmp uge i64 %P, 42
br i1 %brcond, label %store, label %bb.backedge
store:
Use modulo semantic to generate non-integer-overflow assumptions This will allow to generate non-wrap assumptions for integer expressions that are part of the SCoP. We compare the common isl representation of the expression with one computed with modulo semantic. For all parameter combinations they are not equal we can have integer overflows. The nsw flags are respected when the modulo representation is computed, nuw and nw flags are ignored for now. In order to not increase compile time to much, the non-wrap assumptions are collected in a separate boundary context instead of the assumed context. This helps compile time as the boundary context can become complex and it is therefor not advised to use it in other operations except runtime check generation. However, the assumed context is e.g., used to tighten dependences. While the boundary context might help to tighten the assumed context it is doubtful that it will help in practice (it does not effect lnt much) as the boundary (or no-wrap assumptions) only restrict the very end of the possible value range of parameters. PET uses a different approach to compute the no-wrap context, though lnt runs have shown that this version performs slightly better for us. llvm-svn: 247732
2015-09-16 06:52:53 +08:00
%scevgep = getelementptr inbounds i64, i64* %a, i64 %i
Add experimental support for unsigned expressions This support is still incomplete and consequently hidden behind a switch that needs to be enabled. One problem is ATM that we incorrectly interpret very large unsigned values as negative values even if used in an unsigned comparision. llvm-svn: 225480
2015-01-09 08:01:33 +08:00
store i64 %i, i64* %scevgep
br label %bb.backedge
bb.backedge:
%i.inc = add nsw i64 %i, 1
%exitcond = icmp eq i64 %i.inc, %N
br i1 %exitcond, label %return, label %bb
return:
ret void
}