commit b218c858606641050d13f35a2365168b89b44841
author Zheng Xu <zheng.xu@arm.com> Mon Dec 08 18:18:01 2014 +0800
committer Zheng Xu <zheng.xu@arm.com> Mon Dec 08 19:03:03 2014 +0800
tree 4fc577f5573be610d0925c827b14e2080453ef3f
parent ab6572b564db69e2877456ca6fbd3a00f4cc4b6b

ART: Clear use count for unused VRs.

The use count of temp VR should be cleared when we replace
"CMP_XXX vA, vB, vC" and "IF_XXX vA" with "kMirOpFusedCmpXXX vB, vC".
Otherwise, the backend may allocate a physical register for the unused vA.

Change-Id: I43ad37d0e7161ec3de154de8888caa94603f7715

compiler/dex/mir_optimization.cc

diff --git a/compiler/dex/mir_optimization.cc b/compiler/dex/mir_optimization.cc
index 3c6b61d..fd4c3d7 100644
--- a/compiler/dex/mir_optimization.cc
+++ b/compiler/dex/mir_optimization.cc
@@ -526,6 +526,9 @@
                 default: LOG(ERROR) << "Unexpected opcode: " << opcode;
               }
               mir->dalvikInsn.opcode = static_cast<Instruction::Code>(kMirOpNop);
+              // Clear use count of temp VR.
+              use_counts_[mir->ssa_rep->defs[0]] = 0;
+              raw_use_counts_[mir->ssa_rep->defs[0]] = 0;
               // Copy the SSA information that is relevant.
               mir_next->ssa_rep->num_uses = mir->ssa_rep->num_uses;
               mir_next->ssa_rep->uses = mir->ssa_rep->uses;