[PATCH] D122084: [X86] combineAddOrSubToADCOrSBB - Fold ADD/SUB + (AND(SRL(X,Y),1) -> ADC/SBB+BT(X,Y)

[Simon Pilgrim via Phabricator via llvm-commits]

RKSimon added inline comments.


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Comment at: llvm/test/CodeGen/X86/add-sub-bool.ll:129
 
 define i32 @test_i32_sub_sub_idx(i32 %x, i32 %y, i32 %z) {
 ; X86-LABEL: test_i32_sub_sub_idx:
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RKSimon wrote:
> pengfei wrote:
> > So the test actually tests for `%x - (%y - bool(%z & (1 << 30))`? The name seems misleading which implies it tests for `test_sub` in PR35256.
> Sorry, I was trying to test all permutations of the adds/subs to see whether any folds stall further optimizations. I'll update the comment at the top.
Ah - this is actually testing another yet combo, not the basic SBB pattern - I'll address this later


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https://reviews.llvm.org/D122084