[PATCH] D155472: [DAG] Attempt shl narrowing in SimplifyDemandedBits (WIP)

[Noah Goldstein via Phabricator via llvm-commits]

goldstein.w.n added inline comments.


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Comment at: llvm/test/CodeGen/X86/2009-05-30-ISelBug.ll:14
+; CHECK-NEXT:    andl $-4, %edx
+; CHECK-NEXT:    movl (%rdi,%rdx), %edx
 ; CHECK-NEXT:    movzbl %dl, %edi
----------------
This seems like a slight regression.


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Comment at: llvm/test/CodeGen/X86/atomic-rm-bit-test-64.ll:1226
 ; CHECK-NEXT:  # %bb.2: # %if.then
+; CHECK-NEXT:    movl %esi, %esi
 ; CHECK-NEXT:    movq (%rdi,%rsi,8), %rax
----------------
hmm?


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Comment at: llvm/test/CodeGen/X86/divmod128.ll:442
+; X86-64-NEXT:    orq %rdi, %rcx
+; X86-64-NEXT:    movq %rcx, %rax
 ; X86-64-NEXT:    xorl %edx, %edx
----------------
Slight regression here.


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Comment at: llvm/test/CodeGen/X86/lsr-loop-exit-cond.ll:76
+; GENERIC-NEXT:    andl $-4, %r14d
+; GENERIC-NEXT:    movzbl 3(%rdi,%r14), %edi
 ; GENERIC-NEXT:    shll $24, %edi
----------------
Another here. It seems some transform that does `shr; AGEN` is breaking down a bit.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D155472/new/

https://reviews.llvm.org/D155472