From: Julian Seward <jseward@acm.org>
Date: Fri, 12 Mar 2021 16:55:46 +0000 (+0100)
Subject: mc_translate.c: enable further uses of DLexpensive for scalar EQ/NE comparisons
X-Git-Tag: VALGRIND_3_17_0~10
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=21571252964c4d7860210cbe9f60a49eb6881824;p=thirdparty%2Fvalgrind.git

mc_translate.c: enable further uses of DLexpensive for scalar EQ/NE comparisons

mc_translate.c: enable further cases where scalar integer EQ/NE comparisons
use expensive instrumentation by default:

  x86, amd64  for 16-bit comparisons
  arm, arm64  for 32-bit comparisons

This fixes 'Bug 434193 - GCC 9+ inlined strcmp causes "Conditional jump or move depends on
uninitialised value" report'.

Patch from Mike Crowe <mac@mcrowe.com>.
---

diff --git a/NEWS b/NEWS
index cd8a509faa..028725c038 100644
--- a/NEWS
+++ b/NEWS
@@ -170,6 +170,7 @@ where XXXXXX is the bug number as listed below.
 433629  valgrind/README has type "abd" instead of "and"
 433641  Rust std::sys::unix::fs::try_statx Syscall param fstatat(file_name)
 433898  arm64: Handle sp, lr, fp as DwReg in CfiExpr
+434193  GCC 9+ inlined strcmp causes "Conditional jump or move [..] value" report
 n-i-bz  helgrind: If hg_cli__realloc fails, return NULL.
 
 
diff --git a/memcheck/mc_translate.c b/memcheck/mc_translate.c
index 516988bdd4..739f67cbf9 100644
--- a/memcheck/mc_translate.c
+++ b/memcheck/mc_translate.c
@@ -8586,17 +8586,22 @@ IRSB* MC_(instrument) ( VgCallbackClosure* closure,
          approximation to the above, and is self-contained.*/
 #     if defined(VGA_x86)
       mce.dlbo.dl_Add32           = DLauto;
+      mce.dlbo.dl_CmpEQ16_CmpNE16 = DLexpensive;
       mce.dlbo.dl_CmpEQ32_CmpNE32 = DLexpensive;
 #     elif defined(VGA_amd64)
       mce.dlbo.dl_Add32           = DLexpensive;
       mce.dlbo.dl_Add64           = DLauto;
+      mce.dlbo.dl_CmpEQ16_CmpNE16 = DLexpensive;
       mce.dlbo.dl_CmpEQ32_CmpNE32 = DLexpensive;
       mce.dlbo.dl_CmpEQ64_CmpNE64 = DLexpensive;
 #     elif defined(VGA_ppc64le)
       // Needed by (at least) set_AV_CR6() in the front end.
       mce.dlbo.dl_CmpEQ64_CmpNE64 = DLexpensive;
 #     elif defined(VGA_arm64)
+      mce.dlbo.dl_CmpEQ32_CmpNE32 = DLexpensive;
       mce.dlbo.dl_CmpEQ64_CmpNE64 = DLexpensive;
+#     elif defined(VGA_arm)
+      mce.dlbo.dl_CmpEQ32_CmpNE32 = DLexpensive;
 #     endif
 
       /* preInstrumentationAnalysis() will allocate &mce.tmpHowUsed and then