<HTML><BODY style="word-wrap: break-word; -khtml-nbsp-mode: space; -khtml-line-break: after-white-space; "><BR><DIV><DIV>On Jul 28, 2007, at 2:26 PM, Evan Cheng wrote:</DIV><BR class="Apple-interchange-newline"><BLOCKQUOTE type="cite"><DIV>On Jul 28, 2007, at 11:52 AM, Christopher Lamb <<A href="mailto:christopher.lamb@gmail.com">christopher.lamb@gmail.com</A>> wrote:<BR></DIV><DIV><BR></DIV><DIV></DIV><BLOCKQUOTE type="cite"><DIV><BR><DIV><DIV>On Jul 28, 2007, at 1:48 AM, Evan Cheng wrote:</DIV><BR class="Apple-interchange-newline"><BLOCKQUOTE type="cite"><DIV>Very cool! I need to read it more carefully. <BR></DIV></BLOCKQUOTE><BR><BLOCKQUOTE type="cite"><DIV>But I see you are lowering zext to a single insert_subreg. Is that right? It won't zero out the top part, no?</DIV></BLOCKQUOTE><DIV><BR class="khtml-block-placeholder"></DIV><DIV>It's only lowering (zext i32 to i64) to an insert_subreg on x86-64 where all writes to 32-bit registers implicitly zero-extend into the upper 32-bits.</DIV><DIV><BR></DIV></DIV></DIV></BLOCKQUOTE><DIV><BR class="webkit-block-placeholder"></DIV>I know. But thy mismatch semantically. A insert_subreg to the lower part should not change the upper half. I think this is only legal for anyext.</BLOCKQUOTE><DIV><BR class="khtml-block-placeholder"></DIV><DIV>On x86-64 the semantics of a 2 operand i32 insert_subreg is that the input super-value is implicitly zero. So in this sense the insert isn't changing the upper half, it's just that the upper half is being set to zero implicitly rather than explicitly. If you'll notice the insert_subreg is a two operand (implicit super value) not a three operand version. If the insert were the three operand version, and the super value as coming from an implicit def I'd agree with you, but it's not.</DIV><DIV><BR class="khtml-block-placeholder"></DIV><DIV>Also the current behavior is to use a 32-bit mov instruction for both zeroext and for anyext, I don't see how this is any different.</DIV><BR><BLOCKQUOTE type="cite"><DIV><BLOCKQUOTE type="cite"><DIV><DIV><DIV>--</DIV><DIV>Chris</DIV><DIV><BR class="khtml-block-placeholder"></DIV><BLOCKQUOTE type="cite"><DIV>Sent from my iPhone</DIV><DIV><BR>On Jul 28, 2007, at 12:17 AM, Christopher Lamb <<A href="mailto:christopher.lamb@gmail.com"></A><A href="mailto:christopher.lamb@gmail.com">christopher.lamb@gmail.com</A>> wrote:<BR><BR></DIV><DIV></DIV><BLOCKQUOTE type="cite"><DIV>This patch changes the X86 back end to use the new subreg operations for appropriate truncate and extend operations. This should allow regression testing of the subreg feature going forward, as it's now used in a public target.<DIV><BR class="khtml-block-placeholder"></DIV><DIV>The patch passed DejaGnu and all of SingleSource on my x86 machine, but there are changes for x86-64 as well which I haven't been able to test. Output assembly for x86-64 appears sane, but I'd appreciate someone giving the patch a try on their x86-64 system. Other 32-bit x86 testing is also appreciated.</DIV><DIV><BR class="khtml-block-placeholder"></DIV><DIV>Thanks<BR><DIV> <SPAN class="Apple-style-span" style="border-collapse: separate; border-spacing: 0px 0px; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; text-align: auto; -khtml-text-decorations-in-effect: none; text-indent: 0px; -apple-text-size-adjust: auto; text-transform: none; orphans: 2; white-space: normal; widows: 2; word-spacing: 0px; "><SPAN class="Apple-style-span" style="border-collapse: separate; border-spacing: 0px 0px; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; text-align: auto; -khtml-text-decorations-in-effect: none; text-indent: 0px; -apple-text-size-adjust: auto; text-transform: none; orphans: 2; white-space: normal; widows: 2; word-spacing: 0px; "><DIV>--</DIV><DIV>Christopher Lamb</DIV><DIV><BR class="khtml-block-placeholder"></DIV></SPAN></SPAN></DIV></DIV></DIV></BLOCKQUOTE><BLOCKQUOTE type="cite"><DIV><x86_subregs.patch></DIV></BLOCKQUOTE><BLOCKQUOTE type="cite"><DIV><DIV><DIV><SPAN class="Apple-style-span" style="border-collapse: separate; border-spacing: 0px 0px; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; text-align: auto; -khtml-text-decorations-in-effect: none; text-indent: 0px; -apple-text-size-adjust: auto; text-transform: none; orphans: 2; white-space: normal; widows: 2; word-spacing: 0px; "><SPAN class="Apple-style-span" style="border-collapse: separate; border-spacing: 0px 0px; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; text-align: auto; -khtml-text-decorations-in-effect: none; text-indent: 0px; -apple-text-size-adjust: auto; text-transform: none; orphans: 2; white-space: normal; widows: 2; word-spacing: 0px; "><BR class="Apple-interchange-newline"></SPAN></SPAN> </DIV><BR></DIV></DIV></BLOCKQUOTE><BLOCKQUOTE type="cite"><DIV><SPAN>_______________________________________________</SPAN><BR><SPAN>llvm-commits mailing list</SPAN><BR><SPAN><A href="mailto:llvm-commits@cs.uiuc.edu"></A><A href="mailto:llvm-commits@cs.uiuc.edu">llvm-commits@cs.uiuc.edu</A></SPAN><BR><SPAN><A href="http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits"></A><A href="http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits">http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits</A></SPAN><BR></DIV></BLOCKQUOTE><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">_______________________________________________</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">llvm-commits mailing list</DIV><DIV style="margin-top: 0px; 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border-spacing: 0px 0px; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; text-align: auto; -khtml-text-decorations-in-effect: none; text-indent: 0px; -apple-text-size-adjust: auto; text-transform: none; orphans: 2; white-space: normal; widows: 2; word-spacing: 0px; "><DIV>--</DIV><DIV>Christopher Lamb</DIV><DIV><BR class="khtml-block-placeholder"></DIV><BR class="Apple-interchange-newline"></SPAN></SPAN> </DIV><BR></DIV></BLOCKQUOTE><BLOCKQUOTE type="cite"><DIV><SPAN>_______________________________________________</SPAN><BR><SPAN>llvm-commits mailing list</SPAN><BR><SPAN><A href="mailto:llvm-commits@cs.uiuc.edu">llvm-commits@cs.uiuc.edu</A></SPAN><BR><SPAN><A href="http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits">http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits</A></SPAN><BR></DIV></BLOCKQUOTE></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">_______________________________________________</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">llvm-commits mailing list</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><A href="mailto:llvm-commits@cs.uiuc.edu">llvm-commits@cs.uiuc.edu</A></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><A href="http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits">http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits</A></DIV> </BLOCKQUOTE></DIV><BR><DIV> <SPAN class="Apple-style-span" style="border-collapse: separate; border-spacing: 0px 0px; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; text-align: auto; -khtml-text-decorations-in-effect: none; text-indent: 0px; -apple-text-size-adjust: auto; text-transform: none; orphans: 2; white-space: normal; widows: 2; word-spacing: 0px; "><SPAN class="Apple-style-span" style="border-collapse: separate; border-spacing: 0px 0px; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; text-align: auto; -khtml-text-decorations-in-effect: none; text-indent: 0px; -apple-text-size-adjust: auto; text-transform: none; orphans: 2; white-space: normal; widows: 2; word-spacing: 0px; "><DIV>--</DIV><DIV>Christopher Lamb</DIV><DIV><BR class="khtml-block-placeholder"></DIV><BR class="Apple-interchange-newline"></SPAN></SPAN> </DIV><BR></BODY></HTML>