<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
<style type="text/css" style="display:none;"><!-- P {margin-top:0;margin-bottom:0;} --></style>
</head>
<body dir="ltr">
<div id="divtagdefaultwrapper" dir="ltr" style="">
<p style="margin-top: 0px; margin-bottom: 0px;"><span style="font-size: 12pt;">Hi,</span><font color="#333333" face="Segoe UI WestEuropean, Segoe UI, -apple-system, BlinkMacSystemFont, Roboto, Helvetica Neue, sans-serif"><span style="font-size: 17px; white-space: nowrap;"></span></font></p>
<p style="color: rgb(0, 0, 0); font-family: Calibri, Helvetica, sans-serif, EmojiFont, "Apple Color Emoji", "Segoe UI Emoji", NotoColorEmoji, "Segoe UI Symbol", "Android Emoji", EmojiSymbols; font-size: 12pt; margin-top: 0px; margin-bottom: 0px;">
<br>
</p>
<p style="color: rgb(0, 0, 0); font-family: Calibri, Helvetica, sans-serif, EmojiFont, "Apple Color Emoji", "Segoe UI Emoji", NotoColorEmoji, "Segoe UI Symbol", "Android Emoji", EmojiSymbols; font-size: 12pt; margin-top: 0px; margin-bottom: 0px;">
I am trying to recreate the compilation of using clang and -O2 by splitting the compilation to the several stages using the several llvm tools (clang as front-end, opt, llc..) but the optimiser seems to behave differently if called individually than when called
by clang. I am using the latest llvm version. So I am calling the front end using:</p>
<p style="color: rgb(0, 0, 0); font-family: Calibri, Helvetica, sans-serif, EmojiFont, "Apple Color Emoji", "Segoe UI Emoji", NotoColorEmoji, "Segoe UI Symbol", "Android Emoji", EmojiSymbols; font-size: 12pt; margin-top: 0px; margin-bottom: 0px;">
<span style="font-size:12pt"><br>
</span></p>
<blockquote style="color: rgb(0, 0, 0); font-family: Calibri, Helvetica, sans-serif, EmojiFont, "Apple Color Emoji", "Segoe UI Emoji", NotoColorEmoji, "Segoe UI Symbol", "Android Emoji", EmojiSymbols; font-size: 12pt; margin: 0px 0px 0px 40px; border: none; padding: 0px;">
<p style="margin-top:0; margin-bottom:0"><span style="font-size:12pt"></span></p>
<div>clang -mllvm -stats -mllvm -debug-pass=Structure -target arm-none-eabi -isystem /usr/local/lpcxpresso_8.2.2_650/lpcxpresso/tools/arm-none-eabi/include -DHAVE_CONFIG_H -I. -I../.. -Wall -I ../../i^Clude -I ../../config/arm/boards/lpcxpresso_1769_xpresso/
-I ../../config/arm/chips/lpc175x_6x/ "-DCALIB_SCALE=0" --static -mthumb -mcpu=cortex-m3 -D__USE_LPCOPEN -D__CODE_RED -D__REDLIB__ -DCHIP_LPC175X_6X -DCORE_M3 -ffunction-sections -fdata-sections -O2 -c -emit-llvm -o adpcm_optimized.bc adpcm.c</div>
<p></p>
</blockquote>
<p style="color: rgb(0, 0, 0); font-family: Calibri, Helvetica, sans-serif, EmojiFont, "Apple Color Emoji", "Segoe UI Emoji", NotoColorEmoji, "Segoe UI Symbol", "Android Emoji", EmojiSymbols; font-size: 12pt; margin-top: 0px; margin-bottom: 0px;">
<span style="font-size:12pt"></span></p>
<div style="color: rgb(0, 0, 0); font-family: Calibri, Helvetica, sans-serif, EmojiFont, "Apple Color Emoji", "Segoe UI Emoji", NotoColorEmoji, "Segoe UI Symbol", "Android Emoji", EmojiSymbols; font-size: 12pt;">
</div>
<div style="color: rgb(0, 0, 0); font-family: Calibri, Helvetica, sans-serif, EmojiFont, "Apple Color Emoji", "Segoe UI Emoji", NotoColorEmoji, "Segoe UI Symbol", "Android Emoji", EmojiSymbols; font-size: 12pt;">
<br>
</div>
<div style="color: rgb(0, 0, 0); font-family: Calibri, Helvetica, sans-serif, EmojiFont, "Apple Color Emoji", "Segoe UI Emoji", NotoColorEmoji, "Segoe UI Symbol", "Android Emoji", EmojiSymbols; font-size: 12pt;">
this also gives me the optimizer statistics and the structure of calling the passes.</div>
<div style="color: rgb(0, 0, 0); font-family: Calibri, Helvetica, sans-serif, EmojiFont, "Apple Color Emoji", "Segoe UI Emoji", NotoColorEmoji, "Segoe UI Symbol", "Android Emoji", EmojiSymbols; font-size: 12pt;">
<br>
</div>
<div style="color: rgb(0, 0, 0); font-family: Calibri, Helvetica, sans-serif, EmojiFont, "Apple Color Emoji", "Segoe UI Emoji", NotoColorEmoji, "Segoe UI Symbol", "Android Emoji", EmojiSymbols; font-size: 12pt;">
then I am using </div>
<span style="font-size: 12pt;"> </span>
<p style="color: rgb(0, 0, 0); font-family: Calibri, Helvetica, sans-serif, EmojiFont, "Apple Color Emoji", "Segoe UI Emoji", NotoColorEmoji, "Segoe UI Symbol", "Android Emoji", EmojiSymbols; font-size: 12pt;">
</p>
<p style="color: rgb(0, 0, 0); font-family: Calibri, Helvetica, sans-serif, EmojiFont, "Apple Color Emoji", "Segoe UI Emoji", NotoColorEmoji, "Segoe UI Symbol", "Android Emoji", EmojiSymbols; font-size: 12pt; margin-top: 0px; margin-bottom: 0px;">
</p>
<blockquote style="color: rgb(0, 0, 0); font-family: Calibri, Helvetica, sans-serif, EmojiFont, "Apple Color Emoji", "Segoe UI Emoji", NotoColorEmoji, "Segoe UI Symbol", "Android Emoji", EmojiSymbols; font-size: 12pt; margin: 0px 0px 0px 40px; border: none; padding: 0px;">
<p><span style="font-size:12pt"></span></p>
<div>clang -mllvm -stats -mllvm -debug-pass=Structure -target arm-none-eabi -isystem /usr/local/lpcxpresso_8.2.2_650/lpcxpresso/tools/arm-none-eabi/include -DHAVE_CONFIG_H -I. -I../.. -Wall -I ../../i^Clude -I ../../config/arm/boards/lpcxpresso_1769_xpresso/
-I ../../config/arm/chips/lpc175x_6x/ "-DCALIB_SCALE=0" --static -mthumb -mcpu=cortex-m3 -D__USE_LPCOPEN -D__CODE_RED -D__REDLIB__ -DCHIP_LPC175X_6X -DCORE_M3 -ffunction-sections -fdata-sections -O0 -c -emit-llvm -o adpcm_no_opt.bc adpcm.c</div>
<div><br>
</div>
<div>and then</div>
<div><br>
</div>
<div><span>opt -stats -O2 -S -debug-pass=Structure adpcm<span style="font-family:Calibri,Helvetica,sans-serif,EmojiFont,"Apple Color Emoji","Segoe UI Emoji",NotoColorEmoji,"Segoe UI Symbol","Android Emoji",EmojiSymbols; font-size:16px">_no_opt</span>.bc -o
adpcm.ll</span><br>
</div>
<div><br>
</div>
</blockquote>
<span style="font-size: 12pt;">I was expecting the stats coming out of the opt call to be the same as calling clang with -O2. Instead they are very little:
</span>
<p style="color: rgb(0, 0, 0); font-family: Calibri, Helvetica, sans-serif, EmojiFont, "Apple Color Emoji", "Segoe UI Emoji", NotoColorEmoji, "Segoe UI Symbol", "Android Emoji", EmojiSymbols; font-size: 12pt;">
</p>
<blockquote style="color: rgb(0, 0, 0); font-family: Calibri, Helvetica, sans-serif, EmojiFont, "Apple Color Emoji", "Segoe UI Emoji", NotoColorEmoji, "Segoe UI Symbol", "Android Emoji", EmojiSymbols; font-size: 12pt; margin: 0px 0px 0px 40px; border: none; padding: 0px;">
<p style="margin-top:0; margin-bottom:0"></p>
<div> 18 basicaa - Number of times a GEP is decomposed</div>
<p></p>
<p style="margin-top:0; margin-bottom:0"></p>
<div> 1 cgscc-passmgr - Maximum CGSCCPassMgr iterations on one SCC</div>
<p></p>
<p style="margin-top:0; margin-bottom:0"></p>
<div>104 globalopt - Number of globals marked unnamed_addr</div>
<p></p>
<p style="margin-top:0; margin-bottom:0"></p>
<div> 6 globalsmodref-aa - Number of global vars without address taken</div>
<p></p>
</blockquote>
<p style="color: rgb(0, 0, 0); font-family: Calibri, Helvetica, sans-serif, EmojiFont, "Apple Color Emoji", "Segoe UI Emoji", NotoColorEmoji, "Segoe UI Symbol", "Android Emoji", EmojiSymbols; font-size: 12pt; margin-top: 0px; margin-bottom: 0px;">
</p>
<div style="color: rgb(0, 0, 0); font-family: Calibri, Helvetica, sans-serif, EmojiFont, "Apple Color Emoji", "Segoe UI Emoji", NotoColorEmoji, "Segoe UI Symbol", "Android Emoji", EmojiSymbols; font-size: 12pt;">
</div>
<div style="color: rgb(0, 0, 0); font-family: Calibri, Helvetica, sans-serif, EmojiFont, "Apple Color Emoji", "Segoe UI Emoji", NotoColorEmoji, "Segoe UI Symbol", "Android Emoji", EmojiSymbols; font-size: 12pt;">
<br>
</div>
<p style="color: rgb(0, 0, 0); font-family: Calibri, Helvetica, sans-serif, EmojiFont, "Apple Color Emoji", "Segoe UI Emoji", NotoColorEmoji, "Segoe UI Symbol", "Android Emoji", EmojiSymbols; font-size: 12pt;">
</p>
<p style="color: rgb(0, 0, 0); font-family: Calibri, Helvetica, sans-serif, EmojiFont, "Apple Color Emoji", "Segoe UI Emoji", NotoColorEmoji, "Segoe UI Symbol", "Android Emoji", EmojiSymbols; font-size: 12pt; margin-top: 0px; margin-bottom: 0px;">
Am I doing something wrong or missing something? The Structure of calling the passes is still the same, and also the emitted code from the clang with -O2 and the opt with -O2 seems to be the same. So why is the optimiser called individually not reporting
the full stats?</p>
<p style="color: rgb(0, 0, 0); font-family: Calibri, Helvetica, sans-serif, EmojiFont, "Apple Color Emoji", "Segoe UI Emoji", NotoColorEmoji, "Segoe UI Symbol", "Android Emoji", EmojiSymbols; font-size: 12pt; margin-top: 0px; margin-bottom: 0px;">
<br>
</p>
<p style="color: rgb(0, 0, 0); font-family: Calibri, Helvetica, sans-serif, EmojiFont, "Apple Color Emoji", "Segoe UI Emoji", NotoColorEmoji, "Segoe UI Symbol", "Android Emoji", EmojiSymbols; font-size: 12pt; margin-top: 0px; margin-bottom: 0px;">
Thank you,</p>
<p style="color: rgb(0, 0, 0); font-family: Calibri, Helvetica, sans-serif, EmojiFont, "Apple Color Emoji", "Segoe UI Emoji", NotoColorEmoji, "Segoe UI Symbol", "Android Emoji", EmojiSymbols; font-size: 12pt; margin-top: 0px; margin-bottom: 0px;">
Kyriakos<br>
</p>
<blockquote style="color: rgb(0, 0, 0); font-family: Calibri, Helvetica, sans-serif, EmojiFont, "Apple Color Emoji", "Segoe UI Emoji", NotoColorEmoji, "Segoe UI Symbol", "Android Emoji", EmojiSymbols; font-size: 12pt; margin: 0px 0px 0px 40px; border: none; padding: 0px;">
<p></p>
</blockquote>
<p style="color: rgb(0, 0, 0); font-family: Calibri, Helvetica, sans-serif, EmojiFont, "Apple Color Emoji", "Segoe UI Emoji", NotoColorEmoji, "Segoe UI Symbol", "Android Emoji", EmojiSymbols; font-size: 12pt;">
<span style="font-size:12pt"><span style="font-family:Calibri,Helvetica,sans-serif,EmojiFont,"Apple Color Emoji","Segoe UI Emoji",NotoColorEmoji,"Segoe UI Symbol","Android Emoji",EmojiSymbols"></span><span style="font-family:Calibri,Helvetica,sans-serif,EmojiFont,"Apple Color Emoji","Segoe UI Emoji",NotoColorEmoji,"Segoe UI Symbol","Android Emoji",EmojiSymbols"></span></span></p>
<div style="color: rgb(0, 0, 0); font-family: Calibri, Helvetica, sans-serif, EmojiFont, "Apple Color Emoji", "Segoe UI Emoji", NotoColorEmoji, "Segoe UI Symbol", "Android Emoji", EmojiSymbols; font-size: 16px;">
</div>
<br>
<p style="color: rgb(0, 0, 0); font-family: Calibri, Helvetica, sans-serif, EmojiFont, "Apple Color Emoji", "Segoe UI Emoji", NotoColorEmoji, "Segoe UI Symbol", "Android Emoji", EmojiSymbols; font-size: 12pt;">
</p>
</div>
</body>
</html>