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| author | Chris Lattner <sabre@nondot.org> | 2008-07-23 05:06:28 +0000 |
|---|---|---|
| committer | Chris Lattner <sabre@nondot.org> | 2008-07-23 05:06:28 +0000 |
| commit | 967948b4e25cae3de68f38fddaa75d838e676dec (patch) | |
| tree | d4a991f40c7367570d36eb6fbd90abaea879d68a /lib/Transforms | |
| parent | a9173801caf73613d3fa07b1094b5539d9223953 (diff) | |
| download | external_llvm-967948b4e25cae3de68f38fddaa75d838e676dec.zip external_llvm-967948b4e25cae3de68f38fddaa75d838e676dec.tar.gz external_llvm-967948b4e25cae3de68f38fddaa75d838e676dec.tar.bz2 | |
"Allow LICM to sink or lift loads from constant memory. Also add a test
case for this.
This allows instructions like loads from global variables declared to
be constant to be moved out of loops."
Patch by Stefanus Du Toit!
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@53945 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/Transforms')
| -rw-r--r-- | lib/Transforms/Scalar/LICM.cpp | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/lib/Transforms/Scalar/LICM.cpp b/lib/Transforms/Scalar/LICM.cpp index f7afaf4..13440c1 100644 --- a/lib/Transforms/Scalar/LICM.cpp +++ b/lib/Transforms/Scalar/LICM.cpp @@ -370,6 +370,11 @@ bool LICM::canSinkOrHoistInst(Instruction &I) { if (LI->isVolatile()) return false; // Don't hoist volatile loads! + // Loads from constant memory are always safe to move, even if they end up + // in the same alias set as something that ends up being modified. + if (AA->pointsToConstantMemory(LI->getOperand(0))) + return true; + // Don't hoist loads which have may-aliased stores in loop. unsigned Size = 0; if (LI->getType()->isSized()) |