diff options
author | Pablo Barrio <pablo.barrio@arm.com> | 2017-12-04 16:55:49 +0000 |
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committer | Pablo Barrio <pablo.barrio@arm.com> | 2017-12-04 16:55:49 +0000 |
commit | 93356784e0e357e3f1f74d565480cc9c25ea4bc9 (patch) | |
tree | cf9bae09ce0e9c8c265005c595bd3675310a9c30 /test | |
parent | 3f2a29c060fb22c270cbfb4f6ad62b614d59ed13 (diff) |
Fix function pointer tail calls in armv8-M.base
Summary:
The compiler fails with the following error message:
fatal error: error in backend: ran out of registers during
register allocation
Tail call optimization for Armv8-M.base fails to meet all the required
constraints when handling calls to function pointers where the
arguments take up r0-r3. This is because the pointer to the
function to be called can only be stored in r0-r3, but these are
all occupied by arguments. This patch makes sure that tail call
optimization does not try to handle this type of calls.
Reviewers: chill, MatzeB, olista01, rengolin, efriedma
Reviewed By: olista01, efriedma
Subscribers: efriedma, aemerson, javed.absar, llvm-commits, kristof.beyls
Differential Revision: https://reviews.llvm.org/D40706
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@319664 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'test')
-rw-r--r-- | test/CodeGen/ARM/v8m-tail-call.ll | 58 |
1 files changed, 58 insertions, 0 deletions
diff --git a/test/CodeGen/ARM/v8m-tail-call.ll b/test/CodeGen/ARM/v8m-tail-call.ll index c369df0c022..96438dc5e64 100644 --- a/test/CodeGen/ARM/v8m-tail-call.ll +++ b/test/CodeGen/ARM/v8m-tail-call.ll @@ -45,3 +45,61 @@ define hidden i32 @f2(i32, i32, i32, i32, i32) { ; CHECK-NEXT: add sp, #4 ; CHECK-NEXT: b h2 } + +; Make sure that tail calls to function pointers that require r0-r3 for argument +; passing do not break the compiler. +@fnptr = global i32 (i32, i32, i32, i32)* null +define i32 @test3() { +; CHECK-LABEL: test3: +; CHECK: blx {{r[0-9]+}} + %1 = load i32 (i32, i32, i32, i32)*, i32 (i32, i32, i32, i32)** @fnptr + %2 = tail call i32 %1(i32 1, i32 2, i32 3, i32 4) + ret i32 %2 +} + +@fnptr2 = global i32 (i32, i32, i64)* null +define i32 @test4() { +; CHECK-LABEL: test4: +; CHECK: blx {{r[0-9]+}} + %1 = load i32 (i32, i32, i64)*, i32 (i32, i32, i64)** @fnptr2 + %2 = tail call i32 %1(i32 1, i32 2, i64 3) + ret i32 %2 +} + +; Check that tail calls to function pointers where not all of r0-r3 are used for +; parameter passing are tail-call optimized. +; test5: params in r0, r1. r2 & r3 are free. +@fnptr3 = global i32 (i32, i32)* null +define i32 @test5() { +; CHECK-LABEL: test5: +; CHECK: ldr [[REG:r[0-9]+]] +; CHECK: bx [[REG]] +; CHECK-NOT: blx [[REG]] + %1 = load i32 (i32, i32)*, i32 (i32, i32)** @fnptr3 + %2 = tail call i32 %1(i32 1, i32 2) + ret i32 %2 +} + +; test6: params in r0 and r2-r3. r1 is free. +@fnptr4 = global i32 (i32, i64)* null +define i32 @test6() { +; CHECK-LABEL: test6: +; CHECK: ldr [[REG:r[0-9]+]] +; CHECK: bx [[REG]] +; CHECK-NOT: blx [[REG]] + %1 = load i32 (i32, i64)*, i32 (i32, i64)** @fnptr4 + %2 = tail call i32 %1(i32 1, i64 2) + ret i32 %2 +} + +; Check that tail calls to functions other than function pointers are +; tail-call optimized. +define i32 @test7() { +; CHECK-LABEL: test7: +; CHECK: b bar +; CHECK-NOT: bl bar + %tail = tail call i32 @bar(i32 1, i32 2, i32 3, i32 4) + ret i32 %tail +} + +declare i32 @bar(i32, i32, i32, i32) |