[PATCH] D80706: [DAGCombine] Add hook to allow target specific test for sqrt input

[Qiu Chaofan via Phabricator via llvm-commits]

qiucf added inline comments.


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Comment at: llvm/include/llvm/CodeGen/TargetLowering.h:4274
+  /// result should be used as the condition operand for a select or branch.
+  virtual SDValue getSqrtInputTest(SDValue Operand, SelectionDAG &DAG,
+                                   const DenormalMode &Mode) const {
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`testSqrtEstimate`?


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Comment at: llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp:21959
+        // Try the target specific test first.
+        SDValue Test = TLI.getSqrtInputTest(Op, DAG, DenormMode);
+        if (!Test) {
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Will it be better if put logic below into base `getSqrtInputTest` implementation?


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Comment at: llvm/lib/Target/PowerPC/PPCISelLowering.cpp:12684-12691
+  // ftsqrt BF,FRB
+  // Let e_b be the unbiased exponent of the double-precision
+  // floating-point operand in register FRB.
+  // fe_flag is set to 1 if either of the following conditions occurs.
+  //   - The double-precision floating-point operand in register FRB is a zero,
+  //     a NaN, or an infinity, or a negative value.
+  //   - e_b is less than or equal to -970.
----------------



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Comment at: llvm/lib/Target/PowerPC/PPCInstrFormats.td:643
   let FRA = 0;
+  let Pattern =  pattern;
 }
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Typo: extra space


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https://reviews.llvm.org/D80706