On Sun, Aug 19, 2012 at 01:21:23PM -0400, Jeff Garzik wrote:
> Hi Jeff,
>
> Have you seen this already?
>
> [penberg@tux sparse]$ cat loop.c
> struct list_node {
> struct list_node *next;
> };
>
> int foo(struct list_node *node)
> {
> int ret = 0;
> while (node) {
> node = node->next;
> ret++;
> }
> return ret;
> }
> [penberg@tux sparse]$ ./sparse-llvm loop.c
> loop.c:5:5: warning: symbol 'foo' was not declared. Should it be static?
> sparse-llvm: Instructions.cpp:730: void llvm::BranchInst::AssertOK():
> Assertion `getCondition()->getType()->isIntegerTy(1) && "May only
> branch on boolean predicates!"' failed.
> Aborted
It doesn't print this particular message anymore, but the llvm
verification detects some other things that could cause problems:
> jonathan@debian:~/dev/sparse/validation$ (../sparse-llvm backend/penberg-loop.c | llvm-dis) 2>&1
> backend/penberg-loop.c:5:5: warning: symbol 'foo' was not declared. Should it be static?
> PHI node operands are not the same type as the result!
> %phi = phi %list_node* [ %0, %L0 ], [ %load_target, %L2 ]
> Instruction does not dominate all uses!
> %phi = phi %list_node* [ %0, %L0 ], [ %load_target, %L2 ]
> %cond = icmp ne %list_node* %phi, null
> Instruction does not dominate all uses!
> %cond = icmp ne %list_node* %phi, null
> br i1 %cond, label %L2, label %L3
> Broken module found, verification continues.
> PHI node operands are not the same type as the result!
> %phi = phi %list_node* [ %0, %L0 ], [ %load_target, %L2 ]
> Instruction does not dominate all uses!
> %phi = phi %list_node* [ %0, %L0 ], [ %load_target, %L2 ]
> %cond = icmp ne %list_node* %phi, null
> Instruction does not dominate all uses!
> %cond = icmp ne %list_node* %phi, null
> br i1 %cond, label %L2, label %L3
> Broken module found, verification continues.
> Broken module found, verification continues.
> ; ModuleID = '<stdin>'
>
> %list_node = type { %list_node* }
>
> define i32 @foo(%list_node*) {
> L0:
> br label %L1
>
> L1: ; preds = %L2, %L0
> %phi = phi %list_node* [ %0, %L0 ], [ %load_target, %L2 ]
> %phi1 = phi i32 [ 0, %L0 ], [ %R5, %L2 ]
> %cond = icmp ne %list_node* %phi, null
> br i1 %cond, label %L2, label %L3
>
> L2: ; preds = %L1
> %src_i = ptrtoint %list_node* %phi to i32
> %addr_i = add i32 %src_i, 0
> %addr = inttoptr i32 %addr_i to i32*
> %load_target = load i32* %addr
This load instruction should use %list_node*.
> %R5 = add i32 %phi1, 1
> br label %L1
>
> L3: ; preds = %L1
> ret i32 %phi1
> }
Jonathan
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