llvm-project/llvm/test/Analysis/ScalarEvolution/max-trip-count.ll

73 lines
2.5 KiB
LLVM

; RUN: opt < %s -analyze -scalar-evolution | FileCheck %s
; ScalarEvolution should be able to understand the loop and eliminate the casts.
; CHECK: {%d,+,sizeof(i32)}
define void @foo(i32* nocapture %d, i32 %n) nounwind {
entry:
%0 = icmp sgt i32 %n, 0 ; <i1> [#uses=1]
br i1 %0, label %bb.nph, label %return
bb.nph: ; preds = %entry
br label %bb
bb: ; preds = %bb1, %bb.nph
%i.02 = phi i32 [ %5, %bb1 ], [ 0, %bb.nph ] ; <i32> [#uses=2]
%p.01 = phi i8 [ %4, %bb1 ], [ -1, %bb.nph ] ; <i8> [#uses=2]
%1 = sext i8 %p.01 to i32 ; <i32> [#uses=1]
%2 = sext i32 %i.02 to i64 ; <i64> [#uses=1]
%3 = getelementptr i32* %d, i64 %2 ; <i32*> [#uses=1]
store i32 %1, i32* %3, align 4
%4 = add i8 %p.01, 1 ; <i8> [#uses=1]
%5 = add i32 %i.02, 1 ; <i32> [#uses=2]
br label %bb1
bb1: ; preds = %bb
%6 = icmp slt i32 %5, %n ; <i1> [#uses=1]
br i1 %6, label %bb, label %bb1.return_crit_edge
bb1.return_crit_edge: ; preds = %bb1
br label %return
return: ; preds = %bb1.return_crit_edge, %entry
ret void
}
; ScalarEvolution should be able to find the maximum tripcount
; of this multiple-exit loop, and if it doesn't know the exact
; count, it should say so.
; PR7845
; CHECK: Loop %for.cond: <multiple exits> Unpredictable backedge-taken count.
; CHECK: Loop %for.cond: max backedge-taken count is 5
@.str = private constant [4 x i8] c"%d\0A\00" ; <[4 x i8]*> [#uses=2]
define i32 @main() nounwind {
entry:
br label %for.cond
for.cond: ; preds = %for.inc, %entry
%g_4.0 = phi i32 [ 0, %entry ], [ %add, %for.inc ] ; <i32> [#uses=5]
%cmp = icmp slt i32 %g_4.0, 5 ; <i1> [#uses=1]
br i1 %cmp, label %for.body, label %for.end
for.body: ; preds = %for.cond
%conv = trunc i32 %g_4.0 to i16 ; <i16> [#uses=1]
%tobool.not = icmp eq i16 %conv, 0 ; <i1> [#uses=1]
%tobool3 = icmp ne i32 %g_4.0, 0 ; <i1> [#uses=1]
%or.cond = and i1 %tobool.not, %tobool3 ; <i1> [#uses=1]
br i1 %or.cond, label %for.end, label %for.inc
for.inc: ; preds = %for.body
%add = add nsw i32 %g_4.0, 1 ; <i32> [#uses=1]
br label %for.cond
for.end: ; preds = %for.body, %for.cond
%call = call i32 (i8*, ...)* @printf(i8* getelementptr inbounds ([4 x i8]* @.str, i64 0, i64 0), i32 %g_4.0) nounwind ; <i32> [#uses=0]
ret i32 0
}
declare i32 @printf(i8*, ...)