switch lowering infinitely loops, chews memory.

[llvmbot]

Bugzilla Link	1197
Resolution	FIXED
Resolved on	Feb 22, 2010 12:51
Version	1.9
OS	All
Attachments	[bytecode obtained by compiling gcchttps://user-images.githubusercontent.com/60944935/143736866-416634fd-b471-4691-b179-dd378ee95df1.gz), bugpoint reduced bytecode
Reporter	LLVM Bugzilla Contributor
CC	@asl

Extended Description

The following llvm bytecode file causes llc
to eat up all memory on my machine then die.
To reproduce, run as follows:
llc exp_attr.bc
This is not x86 specific, since
llc -march=ppc32 exp_attr.bc
also uses up vast (maybe infinite) amounts
of memory. However the C backend works ok.
I'll attach the bytecode file in a second.

[llvmbot]

assigned to @lattner

[llvmbot]

Same attachment as assembly

[lattner]

testing a patch

[lattner]

Fixed. Testcase here: test/CodeGen/Generic/switch-lower.ll

Patch here:
http://lists.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20070212/044404.html

-Chris

[asl]

switch lowering is still broken somehow.

Consider the folowing code:

define i32 @​main(i32 %argc, i8** %argv) {
old_entry1:
br label %cond_next
cond_next:
%not.tmp14 = icmp slt i32 %argc, 11
%hvar2 = zext i1 %not.tmp14 to i32
switch i32 %hvar2, label %old_entry [
i32 -2, label %cond_true
i32 -1, label %cond_next
i32 0, label %cond_true15
i32 1, label %cond_next22
]
cond_true15:
ret i32 1
cond_true:
ret i32 2
cond_next22:
ret i32 3
old_entry:
ret i32 4
}

(Yes, I know, that cases -1 and -2 are really dead).

Resulting binary will always produce result code 4. Commenting out "-1" and "-2"
cases will fix the problem.

[lattner]

Moving new bug to a new bugzilla: Bug 1219.

The original issue is fixed.

-Chris