Auto merge of #49479 - nox:merge-funcs, r=<try>

Reenable the MergeFunctions pass

The crash that happened in #23566 doesn't happen anymore with the LLVM mergefunc
pass enabled and it hugely reduces code size (for example it shaves off 10% of the
final Servo executable). This patch reenables it.

For those wondering, [here are the docs from LLVM about this pass](http://llvm.org/docs/MergeFunctions.html).

Author: bors

.travis.yml

@@ -13,16 +13,16 @@ matrix:
   include:
     # Images used in testing PR and try-build should be run first.
     - env: IMAGE=x86_64-gnu-llvm-3.9 RUST_BACKTRACE=1
-      if: type = pull_request OR branch = auto
+      if: type = disabled
 
     - env: IMAGE=dist-x86_64-linux DEPLOY=1
-      if: branch = try OR branch = auto
+      if: type = disabled
 
     # "alternate" deployments, these are "nightlies" but have LLVM assertions
     # turned on, they're deployed to a different location primarily for
     # additional testing.
     - env: IMAGE=dist-x86_64-linux DEPLOY_ALT=1 CI_JOB_NAME=dist-x86_64-linux-alt
-      if: branch = try OR branch = auto
+      if: type = disabled
 
     - env: >
         RUST_CHECK_TARGET=dist
@@ -112,8 +112,8 @@ matrix:
       if: branch = auto
     - env: IMAGE=armhf-gnu
       if: branch = auto
-    - env: IMAGE=dist-various-1 DEPLOY=1
-      if: branch = auto
+    - env: IMAGE=dist-various-1 DEPLOY_ALT=1
+      if: branch = try
     - env: IMAGE=dist-various-2 DEPLOY=1
       if: branch = auto
     - env: IMAGE=dist-aarch64-linux DEPLOY=1
@@ -177,7 +177,7 @@ matrix:
     - env: IMAGE=x86_64-gnu-distcheck
       if: branch = auto
     - env: IMAGE=mingw-check
-      if: type = pull_request OR branch = auto
+      if: type = disabled
 
     - stage: publish toolstate
       if: branch = master AND type = push

src/llvm

@@ -430,8 +430,7 @@ extern "C" void LLVMRustConfigurePassManagerBuilder(
     LLVMPassManagerBuilderRef PMBR, LLVMRustCodeGenOptLevel OptLevel,
     bool MergeFunctions, bool SLPVectorize, bool LoopVectorize, bool PrepareForThinLTO,
     const char* PGOGenPath, const char* PGOUsePath) {
-  // Ignore mergefunc for now as enabling it causes crashes.
-  // unwrap(PMBR)->MergeFunctions = MergeFunctions;
+  unwrap(PMBR)->MergeFunctions = MergeFunctions;
   unwrap(PMBR)->SLPVectorize = SLPVectorize;
   unwrap(PMBR)->OptLevel = fromRust(OptLevel);
   unwrap(PMBR)->LoopVectorize = LoopVectorize;