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author | Akira Hatanaka <ahatanaka@mips.com> | 2013-09-28 00:12:32 +0000 |
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committer | Akira Hatanaka <ahatanaka@mips.com> | 2013-09-28 00:12:32 +0000 |
commit | 6ff59a16a05d43fdda587ce600b5b42a63cf3d33 (patch) | |
tree | 4a9693eab502c4dbff8219cf9e17ea009803e7e6 /test/CodeGen/Mips/lazy-binding.ll | |
parent | e5f32cf3207da58359a6e3aeeb5b01205645f710 (diff) | |
download | external_llvm-6ff59a16a05d43fdda587ce600b5b42a63cf3d33.zip external_llvm-6ff59a16a05d43fdda587ce600b5b42a63cf3d33.tar.gz external_llvm-6ff59a16a05d43fdda587ce600b5b42a63cf3d33.tar.bz2 |
[mips] Make sure loads from lazy-binding entries do not get CSE'd or hoisted out
of loops.
Previously, two consecutive calls to function "func" would result in the
following sequence of instructions:
1. load $16, %got(func)($gp) // load address of lazy-binding stub.
2. move $25, $16
3. jalr $25 // jump to lazy-binding stub.
4. nop
5. move $25, $16
6. jalr $25 // jump to lazy-binding stub again.
With this patch, the second call directly jumps to func's address, bypassing
the lazy-binding resolution routine:
1. load $25, %got(func)($gp) // load address of lazy-binding stub.
2. jalr $25 // jump to lazy-binding stub.
3. nop
4. load $25, %got(func)($gp) // load resolved address of func.
5. jalr $25 // directly jump to func.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@191591 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'test/CodeGen/Mips/lazy-binding.ll')
-rw-r--r-- | test/CodeGen/Mips/lazy-binding.ll | 41 |
1 files changed, 41 insertions, 0 deletions
diff --git a/test/CodeGen/Mips/lazy-binding.ll b/test/CodeGen/Mips/lazy-binding.ll new file mode 100644 index 0000000..839155a --- /dev/null +++ b/test/CodeGen/Mips/lazy-binding.ll @@ -0,0 +1,41 @@ +; RUN: llc -march=mipsel < %s | FileCheck %s + +; CHECK-LABEL: foo6: +; CHECK: %while.body +; CHECK: lw $25, %call16(foo2)(${{[0-9]+}}) +; CHECK: jalr $25 +; CHECK: %while.end + +define void @foo6(i32 %n) { +entry: + %tobool1 = icmp eq i32 %n, 0 + br i1 %tobool1, label %while.end, label %while.body + +while.body: ; preds = %entry, %while.body + %n.addr.02 = phi i32 [ %dec, %while.body ], [ %n, %entry ] + %dec = add nsw i32 %n.addr.02, -1 + tail call void @foo2() + %tobool = icmp eq i32 %dec, 0 + br i1 %tobool, label %while.end, label %while.body + +while.end: ; preds = %while.body, %entry + ret void +} + +declare void @foo2() + +; CHECK-LABEL: foo1: +; CHECK: lw $25, %call16(foo2)(${{[0-9]+}}) +; CHECK: jalr $25 +; CHECK: lw $25, %call16(foo2)(${{[0-9]+}}) +; CHECK: jalr $25 +; CHECK: lw $25, %call16(foo2)(${{[0-9]+}}) +; CHECK: jalr $25 + +define void @foo1() { +entry: + tail call void @foo2() + tail call void @foo2() + tail call void @foo2() + ret void +} |