From 85733840109907e1e0f8ffc03dcd2f5fd8e49d47 Mon Sep 17 00:00:00 2001 From: Matthias Braun Date: Fri, 11 Oct 2013 19:04:37 +0000 Subject: Remove kill flags after if conversion if necessary When if converting something like: true: ... = R0 false: ... = R0 then the instructions of the true block must not have a flag anymore, as the instruction of the false block follow and do still read the R0 value. Specifically this patch determines the set of register live-in in the false block (possibly after simulating the liveness changes of the duplicated instructions). Each of these live-in registers mustn't be killed. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@192482 91177308-0d34-0410-b5e6-96231b3b80d8 --- test/CodeGen/ARM/ifconv-kills.ll | 30 ++++++++++++++++++++++++++++++ 1 file changed, 30 insertions(+) create mode 100644 test/CodeGen/ARM/ifconv-kills.ll (limited to 'test') diff --git a/test/CodeGen/ARM/ifconv-kills.ll b/test/CodeGen/ARM/ifconv-kills.ll new file mode 100644 index 0000000..bf54ba2 --- /dev/null +++ b/test/CodeGen/ARM/ifconv-kills.ll @@ -0,0 +1,30 @@ +; RUN: llc < %s -march arm -mcpu swift -verify-machineinstrs + +declare i32 @f(i32 %p0, i32 %p1) + +define i32 @foo(i32* %ptr) { +entry: + %cmp = icmp ne i32* %ptr, null + br i1 %cmp, label %if.then, label %if.else + +; present something which can be easily if-converted +if.then: + ; %R0 should be killed here + %valt = load i32* %ptr, align 4 + br label %return + +if.else: + ; %R0 should be killed here, however after if-conversion the %R0 kill + ; has to be removed because if.then will follow after this and still + ; read it. + %addr = getelementptr inbounds i32* %ptr, i32 4 + %vale = load i32* %addr, align 4 + br label %return + +return: + %phival = phi i32 [ %valt, %if.then ], [ %vale, %if.else ] + ; suggest to bring %phival/%valt/%vale into %R1 (because otherwise there + ; will be no kills in if.then/if.else) + %retval = call i32 @f (i32 0, i32 %phival) + ret i32 %retval +} -- cgit v1.1