[libc-commits] [flang] [llvm] [compiler-rt] [clang-tools-extra] [libc] [lldb] [clang] [GlobalIsel] Combine select of binops (PR #76763)
Matt Arsenault via libc-commits
libc-commits at lists.llvm.org
Thu Jan 4 03:43:03 PST 2024
Thorsten =?utf-8?q?Schütt?= <schuett at gmail.com>,
Thorsten =?utf-8?q?Schütt?= <schuett at gmail.com>,
Thorsten =?utf-8?q?Schütt?= <schuett at gmail.com>
Message-ID:
In-Reply-To: <llvm.org/llvm/llvm-project/pull/76763 at github.com>
================
@@ -6548,6 +6534,54 @@ bool CombinerHelper::tryFoldBoolSelectToLogic(GSelect *Select,
return false;
}
+bool CombinerHelper::tryFoldSelectOfBinOps(GSelect *Select,
+ BuildFnTy &MatchInfo) {
+ Register DstReg = Select->getReg(0);
+ Register Cond = Select->getCondReg();
+ Register False = Select->getFalseReg();
+ Register True = Select->getTrueReg();
+ LLT DstTy = MRI.getType(DstReg);
+
+ GBinOp *LHS = getOpcodeDef<GBinOp>(True, MRI);
+ GBinOp *RHS = getOpcodeDef<GBinOp>(False, MRI);
+
+ // We need two binops of the same kind on the true/false registers.
+ if (!LHS || !RHS || LHS->getOpcode() != RHS->getOpcode())
+ return false;
+
+ // Note that there are no constraints on CondTy.
+ unsigned Flags = (LHS->getFlags() & RHS->getFlags()) | Select->getFlags();
----------------
arsenm wrote:
I would have split this by matching the DAG behavior in the initial commit but doesn't really matter. I *think* this is OK but would be nice to have alive verify
https://github.com/llvm/llvm-project/pull/76763
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