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From: "tkoenig at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug rtl-optimization/100622] Conversion to smaller unsigned type in loop Date: Mon, 17 May 2021 09:05:26 +0000 [thread overview] Message-ID: <bug-100622-4-nzk28FHkYD@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-100622-4@http.gcc.gnu.org/bugzilla/> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100622 Thomas Koenig <tkoenig at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|SUSPENDED |UNCONFIRMED Ever confirmed|1 |0 --- Comment #2 from Thomas Koenig <tkoenig at gcc dot gnu.org> --- So, with recent trunk now. [tkoenig@gcc135 tmp]$ gcc -v Es werden eingebaute Spezifikationen verwendet. COLLECT_GCC=gcc COLLECT_LTO_WRAPPER=/home/tkoenig/libexec/gcc/powerpc64le-unknown-linux-gnu/12.0.0/lto-wrapper Ziel: powerpc64le-unknown-linux-gnu Konfiguriert mit: ../trunk/configure --prefix=/home/tkoenig --enable-languages=c,c++,fortran Thread-Modell: posix Unterstützte LTO-Kompressionsalgorithmen: zlib gcc-Version 12.0.0 20210516 (experimental) (GCC) [tkoenig@gcc135 tmp]$ cat add.c unsigned int foo(unsigned int *a, int n) { int i; unsigned int res = 0; for (i=0; i<n; i++) res += a[i]; return res; } unsigned int foo2 (unsigned int *a, int n) { int i; unsigned long res = 0; for (i=0; i<n; i++) res += a[i]; return res; } [tkoenig@gcc135 tmp]$ gcc -O -c add.c && objdump --disassemble add.o add.o: file format elf64-powerpcle Disassembly of section .text: 0000000000000000 <foo>: 0: 00 00 04 2c cmpwi r4,0 4: 30 00 81 40 ble 34 <foo+0x34> 8: 20 00 89 78 clrldi r9,r4,32 c: fc ff 43 39 addi r10,r3,-4 10: 00 00 60 38 li r3,0 14: a6 03 29 7d mtctr r9 18: 04 00 0a 85 lwzu r8,4(r10) 1c: 14 1a 68 7c add r3,r8,r3 20: 20 00 63 78 clrldi r3,r3,32 24: ff ff 29 39 addi r9,r9,-1 28: 20 00 29 79 clrldi r9,r9,32 2c: ec ff 00 42 bdnz 18 <foo+0x18> 30: 20 00 80 4e blr 34: 00 00 60 38 li r3,0 38: 20 00 80 4e blr ... 0000000000000048 <foo2>: 48: 00 00 04 2c cmpwi r4,0 4c: 30 00 81 40 ble 7c <foo2+0x34> 50: 20 00 89 78 clrldi r9,r4,32 54: fc ff 43 39 addi r10,r3,-4 58: 00 00 60 38 li r3,0 5c: a6 03 29 7d mtctr r9 60: 04 00 0a 85 lwzu r8,4(r10) 64: 14 42 63 7c add r3,r3,r8 68: ff ff 29 39 addi r9,r9,-1 6c: 20 00 29 79 clrldi r9,r9,32 70: f0 ff 00 42 bdnz 60 <foo2+0x18> 74: 20 00 63 78 clrldi r3,r3,32 78: 20 00 80 4e blr 7c: 00 00 60 38 li r3,0 80: f4 ff ff 4b b 74 <foo2+0x2c> With -O2 -fno-unroll-loops (foo only): 0000000000000000 <foo>: 0: 00 00 04 2c cmpwi r4,0 4: 3c 00 81 40 ble 40 <foo+0x40> 8: 20 00 8a 78 clrldi r10,r4,32 c: fc ff 23 39 addi r9,r3,-4 10: a6 03 49 7d mtctr r10 14: 00 00 60 38 li r3,0 18: 00 00 00 60 nop 1c: 00 00 42 60 ori r2,r2,0 20: 04 00 49 85 lwzu r10,4(r9) 24: 14 1a 6a 7c add r3,r10,r3 28: 20 00 63 78 clrldi r3,r3,32 2c: f4 ff 00 42 bdnz 20 <foo+0x20> 30: 20 00 80 4e blr 34: 00 00 00 60 nop 38: 00 00 00 60 nop 3c: 00 00 42 60 ori r2,r2,0 40: 00 00 60 38 li r3,0 44: 20 00 80 4e blr ... 54: 00 00 00 60 nop 58: 00 00 00 60 nop 5c: 00 00 42 60 ori r2,r2,0 The clrldi is still in there.
next prev parent reply other threads:[~2021-05-17 9:05 UTC|newest] Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-05-16 8:37 [Bug rtl-optimization/100622] New: " tkoenig at gcc dot gnu.org 2021-05-17 8:46 ` [Bug rtl-optimization/100622] " tkoenig at gcc dot gnu.org 2021-05-17 9:05 ` tkoenig at gcc dot gnu.org [this message] 2021-05-17 12:41 ` rguenth at gcc dot gnu.org 2021-05-17 13:39 ` tkoenig at gcc dot gnu.org 2021-05-17 22:02 ` segher at gcc dot gnu.org 2021-06-08 6:25 ` guojiufu at gcc dot gnu.org 2021-06-08 12:08 ` segher at gcc dot gnu.org 2021-09-17 6:49 ` pinskia at gcc dot gnu.org
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