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author | Chris Lattner <sabre@nondot.org> | 2008-11-26 00:26:16 +0000 |
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committer | Chris Lattner <sabre@nondot.org> | 2008-11-26 00:26:16 +0000 |
commit | 2efbbb38ba7b9601202f2271301f07195dea8959 (patch) | |
tree | a5cfb199a202b4901c74c9c4823cf3e01aa9ad22 /lib | |
parent | 6d235bb7a05c17f1c06def0c1c249150b7e9a53a (diff) | |
download | external_llvm-2efbbb38ba7b9601202f2271301f07195dea8959.zip external_llvm-2efbbb38ba7b9601202f2271301f07195dea8959.tar.gz external_llvm-2efbbb38ba7b9601202f2271301f07195dea8959.tar.bz2 |
Teach CodeGenPrepare to look through Bitcast instructions when attempting to
optimize addressing modes. This allows us to optimize things like isel-sink2.ll
into:
movl 4(%esp), %eax
cmpb $0, 4(%eax)
jne LBB1_2 ## F
LBB1_1: ## TB
movl $4, %eax
ret
LBB1_2: ## F
movzbl 7(%eax), %eax
ret
instead of:
_test:
movl 4(%esp), %eax
cmpb $0, 4(%eax)
leal 4(%eax), %eax
jne LBB1_2 ## F
LBB1_1: ## TB
movl $4, %eax
ret
LBB1_2: ## F
movzbl 3(%eax), %eax
ret
This shrinks (e.g.) 403.gcc from 1133510 to 1128345 lines of .s.
Note that the 2008-10-16-SpillerBug.ll testcase is dubious at best, I doubt
it is really testing what it thinks it is.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@60068 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib')
-rw-r--r-- | lib/Transforms/Scalar/CodeGenPrepare.cpp | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/lib/Transforms/Scalar/CodeGenPrepare.cpp b/lib/Transforms/Scalar/CodeGenPrepare.cpp index 4ba8091..0306b06 100644 --- a/lib/Transforms/Scalar/CodeGenPrepare.cpp +++ b/lib/Transforms/Scalar/CodeGenPrepare.cpp @@ -636,6 +636,17 @@ bool AddressingModeMatcher::MatchOperationAddr(User *AddrInst, unsigned Opcode, TLI.getPointerTy()) return MatchAddr(AddrInst->getOperand(0), Depth); return false; + case Instruction::BitCast: + // BitCast is always a noop, and we can handle it as long as it is + // int->int or pointer->pointer (we don't want int<->fp or something). + if ((isa<PointerType>(AddrInst->getOperand(0)->getType()) || + isa<IntegerType>(AddrInst->getOperand(0)->getType())) && + // Don't touch identity bitcasts. These were probably put here by LSR, + // and we don't want to mess around with them. Assume it knows what it + // is doing. + AddrInst->getOperand(0)->getType() != AddrInst->getType()) + return MatchAddr(AddrInst->getOperand(0), Depth); + return false; case Instruction::Add: { // Check to see if we can merge in the RHS then the LHS. If so, we win. ExtAddrMode BackupAddrMode = AddrMode; |