[llvm] [AMDGPU] Update log lowering to remove contract for AMDGCN backend (PR #168916)

[Matt Arsenault via llvm-commits]

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@@ -2804,10 +2804,9 @@ SDValue AMDGPUTargetLowering::LowerFLOGCommon(SDValue Op,
 
     SDValue C = DAG.getConstantFP(IsLog10 ? c_log10 : c_log, DL, VT);
     SDValue CC = DAG.getConstantFP(IsLog10 ? cc_log10 : cc_log, DL, VT);
-    // Our implementation of LOG is not contract safe because we generate
-    // error-correcting summations for which contraction may lead to an increase
-    // in the error of the approximation. Disable contraction for the expanded
-    // instructions.
+    // Our implementation of LOG is not contract safe because we add correction
+    // terms for which contraction may lead to an increase in the error of the
+    // approximation. Disable contraction for the expanded instructions.
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arsenm wrote:

```suggestion
    // This adds correction terms for which contraction may lead to an increase in 
    // the error of the approximation, so disable it.
```

https://github.com/llvm/llvm-project/pull/168916