From a4e6397fd9f2fbbd6affdfb0738813918cb21da0 Mon Sep 17 00:00:00 2001 From: Jakob Stoklund Olesen Date: Mon, 25 Jun 2012 18:18:27 +0000 Subject: Enforce stricter liveness rules for PHIs. Verify that all paths from the entry block to a virtual register read pass through a def. Enable this check even when MRI->isSSA() is false. Verify that the live range of a virtual register is live out of all predecessor blocks, even for PHI-values. This requires that PHIElimination sometimes inserts IMPLICIT_DEF instruction in predecessor blocks. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@159150 91177308-0d34-0410-b5e6-96231b3b80d8 --- test/CodeGen/Generic/undef-phi.ll | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+) create mode 100644 test/CodeGen/Generic/undef-phi.ll (limited to 'test/CodeGen/Generic') diff --git a/test/CodeGen/Generic/undef-phi.ll b/test/CodeGen/Generic/undef-phi.ll new file mode 100644 index 0000000..10899f9 --- /dev/null +++ b/test/CodeGen/Generic/undef-phi.ll @@ -0,0 +1,26 @@ +; RUN: llc < %s -verify-machineinstrs -verify-coalescing +; +; This function has a PHI with one undefined input. Verify that PHIElimination +; inserts an IMPLICIT_DEF instruction in the predecessor so all paths to the use +; pass through a def. + +%struct.xx_stack = type { i32, %struct.xx_stack* } + +define i32 @push(%struct.xx_stack* %stack) nounwind uwtable readonly ssp { +entry: + %tobool1 = icmp eq %struct.xx_stack* %stack, null + br i1 %tobool1, label %for.end, label %for.body + +for.body: + %stack.addr.02 = phi %struct.xx_stack* [ %0, %for.body ], [ %stack, %entry ] + %next = getelementptr inbounds %struct.xx_stack* %stack.addr.02, i64 0, i32 1 + %0 = load %struct.xx_stack** %next, align 8 + %tobool = icmp eq %struct.xx_stack* %0, null + br i1 %tobool, label %for.end, label %for.body + +for.end: + %top.0.lcssa = phi %struct.xx_stack* [ undef, %entry ], [ %stack.addr.02, %for.body ] + %first = getelementptr inbounds %struct.xx_stack* %top.0.lcssa, i64 0, i32 0 + %1 = load i32* %first, align 4 + ret i32 %1 +} -- cgit v1.1