From 553b1d3dd5b9253ebdf66ee3260c717d5b807dd1 Mon Sep 17 00:00:00 2001 From: Uros Bizjak Date: Thu, 3 Nov 2022 14:17:42 +0100 Subject: [PATCH] i386: Fix uninitialized register after peephole2 conversion [PR107404] MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit The eliminate reg-reg move by inverting the condition of a cmove #2 peephole2 converts the following sequence: 473: bx:DI=[r14:DI*0x8+r12:DI] 960: r15:DI=r8:DI 485: {flags:CCC=cmp(r15:DI+bx:DI,bx:DI);r15:DI=r15:DI+bx:DI;} 737: r15:DI={(geu(flags:CCC,0))?r15:DI:bx:DI} to: 1110: {flags:CCC=cmp(r8:DI+bx:DI,bx:DI);r8:DI=r8:DI+bx:DI;} 1111: r15:DI=[r14:DI*0x8+r12:DI] 1112: r15:DI={(geu(flags:CCC,0))?r8:DI:r15:DI} Please note that(insn 1110) uses register BX, but its initialization was eliminated. Avoid conversion if eliminated move intialized a register, used in the moved instruction. 2022-11-03 Uroš Bizjak gcc/ChangeLog: PR target/107404 * config/i386/i386.md (eliminate reg-reg move by inverting the condition of a cmove #2 peephole2): Check if eliminated move initialized a register, used in the moved instruction. gcc/testsuite/ChangeLog: PR target/107404 * g++.target/i386/pr107404.C: New test. --- gcc/config/i386/i386.md | 3 +- gcc/testsuite/g++.target/i386/pr107404.C | 53 ++++++++++++++++++++++++++++++++ 2 files changed, 55 insertions(+), 1 deletion(-) create mode 100644 gcc/testsuite/g++.target/i386/pr107404.C diff --git a/gcc/config/i386/i386.md b/gcc/config/i386/i386.md index 8556798..436eabb6 100644 --- a/gcc/config/i386/i386.md +++ b/gcc/config/i386/i386.md @@ -21800,7 +21800,8 @@ && REGNO (operands[2]) != REGNO (operands[1]) && peep2_reg_dead_p (2, operands[1]) && peep2_reg_dead_p (4, operands[2]) - && !reg_overlap_mentioned_p (operands[0], operands[3])" + && !reg_overlap_mentioned_p (operands[0], operands[3]) + && !reg_mentioned_p (operands[2], operands[6])" [(parallel [(set (match_dup 7) (match_dup 8)) (set (match_dup 1) (match_dup 9))]) (set (match_dup 0) (match_dup 3)) diff --git a/gcc/testsuite/g++.target/i386/pr107404.C b/gcc/testsuite/g++.target/i386/pr107404.C new file mode 100644 index 0000000..e47d0fd --- /dev/null +++ b/gcc/testsuite/g++.target/i386/pr107404.C @@ -0,0 +1,53 @@ +// PR target/107404 +// { dg-do run } +// { dg-options "-O3" } + +unsigned long long a; +void b(unsigned long long *f, int p2) { *f ^= p2; } +long c; +char e, i; +short g, m; +long long ab[1][25][21][22]; +unsigned long long aa[1][21][22]; +unsigned long long ae[1][25][21][21]; +long long ac[129360]; +char ad[25][1][21]; +char ah[1][25][1][21]; +short af[100]; +long max(long f, unsigned long p2) { return f < p2 ? p2 : f; } +const int &max2(const int &f, const int &p2) { return f < p2 ? p2 : f; } +void foo(unsigned f, unsigned p2, char l, char p4, long long n[][25][21][22], + unsigned long long p6[][21][22], unsigned long long u[][25][21][21]) { + long an; + for (int j = 0; j < 4; j = p2) + for (short k = 0; k < 7; k += 2) + for (short o = 0; o < (short)p2 + 21742; o = l) { + for (signed char p = 2; p < 9; p += p4) + if (p6[j][o][p]) + for (long q(3); 4 ? n[0][k][o][0] : 0; + q += p6[0][o][0] ? p6[j][0][p] : 0) + ac[j + q] = 5066799590; + for (long r(p4 - 16); r < 21; r += 4) { + ad[k][o][r] = max(u[j][k][o][r], f + u[j][k][o][r]); + long d = u[j][k][o][r]; + an = d < p2 ? p2 : d; + e = ah[j][k][o][r] = an; + af[o * r] = i; + } + for (short s(c); s < (short)p2; s = 2) + for (short am(m); am; am = max2(3, p2)) + for (long y = 0; y; y = 3) + for (short t(0); t < max2(g, 0);) + ; + } +} +int main() { + foo(7, 1558227751, 104, 16, ab, aa, ae); + for (unsigned long v = 0; v < 5; ++v) + for (unsigned long w = 0; w < 1; ++w) + for (unsigned long x = 0; x < 21; ++x) + b(&a, ad[v][w][x]); + + if (a) + __builtin_abort(); +} -- 2.7.4