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author | Evan Cheng <evan.cheng@apple.com> | 2012-12-10 23:21:26 +0000 |
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committer | Evan Cheng <evan.cheng@apple.com> | 2012-12-10 23:21:26 +0000 |
commit | 376642ed620ecae05b68c7bc81f79aeb2065abe0 (patch) | |
tree | 9757b2568050b3ab58af15c234df3bc9f66202b0 /include | |
parent | 2b475922e6169098606006a69d765160caa77848 (diff) | |
download | llvm-376642ed620ecae05b68c7bc81f79aeb2065abe0.tar.gz llvm-376642ed620ecae05b68c7bc81f79aeb2065abe0.tar.bz2 llvm-376642ed620ecae05b68c7bc81f79aeb2065abe0.tar.xz |
Some enhancements for memcpy / memset inline expansion.
1. Teach it to use overlapping unaligned load / store to copy / set the trailing
bytes. e.g. On 86, use two pairs of movups / movaps for 17 - 31 byte copies.
2. Use f64 for memcpy / memset on targets where i64 is not legal but f64 is. e.g.
x86 and ARM.
3. When memcpy from a constant string, do *not* replace the load with a constant
if it's not possible to materialize an integer immediate with a single
instruction (required a new target hook: TLI.isIntImmLegal()).
4. Use unaligned load / stores more aggressively if target hooks indicates they
are "fast".
5. Update ARM target hooks to use unaligned load / stores. e.g. vld1.8 / vst1.8.
Also increase the threshold to something reasonable (8 for memset, 4 pairs
for memcpy).
This significantly improves Dhrystone, up to 50% on ARM iOS devices.
rdar://12760078
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@169791 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'include')
-rw-r--r-- | include/llvm/Target/TargetLowering.h | 22 |
1 files changed, 17 insertions, 5 deletions
diff --git a/include/llvm/Target/TargetLowering.h b/include/llvm/Target/TargetLowering.h index 48083eee57..d2e20107ef 100644 --- a/include/llvm/Target/TargetLowering.h +++ b/include/llvm/Target/TargetLowering.h @@ -371,6 +371,16 @@ public: return false; } + /// isIntImmLegal - Returns true if the target can instruction select the + /// specified integer immediate natively (that is, it's materialized with one + /// instruction). The current *assumption* in isel is all of integer + /// immediates are "legal" and only the memcpy / memset expansion code is + /// making use of this. The rest of isel doesn't have proper cost model for + /// immediate materialization. + virtual bool isIntImmLegal(const APInt &/*Imm*/, EVT /*VT*/) const { + return true; + } + /// isShuffleMaskLegal - Targets can use this to indicate that they only /// support *some* VECTOR_SHUFFLE operations, those with specific masks. /// By default, if a target supports the VECTOR_SHUFFLE node, all mask values @@ -678,12 +688,14 @@ public: } /// This function returns true if the target allows unaligned memory accesses. - /// of the specified type. This is used, for example, in situations where an - /// array copy/move/set is converted to a sequence of store operations. It's - /// use helps to ensure that such replacements don't generate code that causes - /// an alignment error (trap) on the target machine. + /// of the specified type. If true, it also returns whether the unaligned + /// memory access is "fast" in the second argument by reference. This is used, + /// for example, in situations where an array copy/move/set is converted to a + /// sequence of store operations. It's use helps to ensure that such + /// replacements don't generate code that causes an alignment error (trap) on + /// the target machine. /// @brief Determine if the target supports unaligned memory accesses. - virtual bool allowsUnalignedMemoryAccesses(EVT) const { + virtual bool allowsUnalignedMemoryAccesses(EVT, bool *Fast = 0) const { return false; } |